Help me fix my hesitation problem

jnorion · Post by **jnorion** » Thu Jan 11, 2007 8:23 pm

This is getting to the point where it's hard to drive so I have to ask for help.

When I bought the car it had a #21 and #35 CEL codes, coolant temp sensor and canister purge solenoid. Several weeks ago I bought a new temp sensor from Napa but didn't have a chance to install it. The car ran fine minus the odd moment of hesitation (half a second or less) and pulled hard when I needed it to.

Two days ago it suddenly started bogging down terribly. Sitting at idle with the clutch in it periodically drops RPMs and shudders for a second. When I first touch the gas after idle it drops, shudders, bogs down for a second, and then revs up. After that it revs fine in neutral. However, when the engine is under load, especially starting from a stop sign or accelerating uphill, it bogs down to the point where it basically can't accelerate at all. I can cruise on the freeway but god help me if I try to pass someone. It takes probably 30 seconds on a flat surface to make it to 60mph.

Yesterday I installed the new temp sensor in the morning and drove to work. It seemed slightly better for 10 or 15 minutes but then was back to the same old crap. I did NOT reset the ECU yesterday because I didn't think about it. Last night I went and bought a new fuel filter thinking that might be the problem, installed it this morning, things feel SLIGHTLY better. After that I reset the ECU by shorting the green and brown plugs at the same time, and then checked codes again. I still have the same two codes even after replacing the sensor, and the car still runs like crap.

Any ideas?

jnorion · Post by **jnorion** » Thu Jan 11, 2007 8:45 pm

Uh oh. I just reread a bunch of stuff trying to get ideas. Apparently connecting the two plugs and driving simply clears the trouble codes and doesn't actually reset the ECU? I'll try the battery dance and see how it goes.

Post by **Legacy777** » Fri Jan 12, 2007 12:48 am

Can you give us a little more info on this sensor you got from NAPA?

Certain things I'm ok with aftermarket parts, but sensors, I'm skittish to use anything but OEM stuff.

jnorion · Post by **jnorion** » Fri Jan 12, 2007 12:58 am

Unfortunately I threw the box away after I installed it so I don't have a part number or anything. I went to Napa and asked for the temp sensor. First they brought me the single wire one that runs the temp gauge. I told them it was the wrong thing so they looked in the book again and then brought me the right one. It looked absolutely identical to what was in there already... it had a single brass probe going into the block and a brown plug housing on the other side with two contacts. It cost about $25, don't remember exactly now.

Update on the situation as well... I unhooked the battery in the parking lot at work today and let it sit, then went back about 50 minutes later, reconnected it, and started the engine. I noticed right away that the idle was not smooth... not lumpy but just shifting up and down between about 600-900 rpm. I let it run for about 15 minutes without touching the throttle, checked the air temperature to make sure the gauge was reading properly, then shut it down. I left work about ten minutes later for the 20 mile/40 minute drive home. For the first five minutes it ran really well, missing just a couple of times but pulling hard. After that it started getting progressively worse again and by the time I got home it was basically back to square one.

EDIT: Also, I could hear it backfiring or something (sounded like it was coming from the cat area rather than the muffler) now and then while I was driving.

Manarius · Post by **Manarius** » Fri Jan 12, 2007 2:28 am

I think your MAF is dirty or burned.

jnorion · Post by **jnorion** » Fri Jan 12, 2007 2:29 am

Hmm. Yeah, I read that you cleaned yours... but I wasn't sure exactly what part you cleaned.

jnorion · Post by **jnorion** » Sat Jan 13, 2007 7:55 am

OK, more observations. It runs perfectly when the engine is cold, and only after it gets up to operating temperature does it start having problems. Also, the problem is intermittent... it will run for ten or fifteen minutes with no trouble and then just go crazy for half an hour or something. It's not consistent.

I also realized that I forgot to check codes again after doing a full ECU reset, but I have a feeling #21 is still there. I'll have to check tomorrow.

kidatari · Post by **kidatari** » Mon Jan 15, 2007 2:17 am

Just to let you know, my car does very similar things, although not quite as bad and I don't throw any CELs. Unfortunately I haven't gotten around to troubleshoot things, but I wanted to let you know that you're not alone

Good luck!

jnorion · Post by **jnorion** » Tue Jan 16, 2007 6:03 am

Checked codes today and sure enough #35 is still there, even after the reset. I think the Napa sensor was probably bad. I'm going to buy an OEM sensor and see if that will take care of it.

Manarius · Post by **Manarius** » Tue Jan 16, 2007 4:45 pm

jnorion wrote:Hmm. Yeah, I read that you cleaned yours... but I wasn't sure exactly what part you cleaned.

I just basically stuck a Q-Tip in rubbing alcohol and then rubbed it over the little metal part inside the tower that sticks down in where the air flows. It's pretty obvious once you look in the MAF from the non-screened side. It looks like......half the size of a dime.

jnorion · Post by **jnorion** » Sun Jan 28, 2007 2:11 am

OK, so I finally had a chance to work on the car a bit today. I was planning to trade MAF sensors with the sedan to see if it fixed the problem but alas, they have different types.

However, I think the MAF sensor really is the problem. I started the car and then went and pulled the plug on the sensor and the engine immediately died. But then I left the plug off and started the car again, and it idled normally. So I closed the hood and drove around the parking lot a bit, and it ran exactly the same as it has been since this problem started... hesitating and noisy but still working. Then, while the engine was running, I plugged the sensor back in, and there was no change. Then I unplugged it again and the engine died.

I repeated this several times to be sure, but the basic outcome is that the engine runs exactly the same whether the MAF sensor is plugged in or not. That's not right, is it?

Then I took the MAF apart. It looked very clean but just in case I cleaned it anyway with rubbing alcohol and a q-tip and tried again. It seemed smoother at idle when I first started it up but felt the same driving it.

jnorion · Post by **jnorion** » Mon Jan 29, 2007 4:05 am

Today's update... I found a new MAF sensor assembly at the U-pull-it for $21. I brought it home and installed it, reset the ECU, and went for a drive. I can't tell if there's a change or not... it bogs horribly starting out but once it gets past that it seems to have good power. I only drove it a little way though, so I haven't really tested it. In any case, I don't think it really fixed the issue, so either that means the MAF sensor was not the problem or the junkyard sensor is also bad.

Any thoughts? Where do I go from here? I guess I'll try replacing the coolant temp sensor with an OEM sensor and see if that makes a difference.

Richard · Post by **Richard** » Mon Jan 29, 2007 11:26 am

How's your electrical connections/grounds doing? Any corrosion?

Or, have you checked to make sure your cat's not clogged? Sounds kinda like a friend who had a really kinked exhaust pipe.

jnorion · Post by **jnorion** » Mon Jan 29, 2007 6:25 pm

Electrical connections as far as I know are fine... the battery terminals were both new two months ago and all the accessories and everything run fine. I suppose I should run a new ground anyway so I may as well do it now to test but I really don't think that's the problem.

I have no idea how to check for a clogged cat. Again, the exhaust system was fine a month and a half ago when I installed a new muffler, but who knows what may have happened since then. There ARE sometimes popping or backfiring noises from the cat area when it hesitates, but it usually feels like it's bogging down before that starts happening.

I also checked gas mileage again and it's down to about 22 in town from 25 mixed town/highway before this problem started. That makes me pretty sure it's not a clogged injector or something of that sort.

jnorion · Post by **jnorion** » Sat Feb 03, 2007 9:13 am

I'm afraid the problem might be more serious than I first thought. At times after driving a lot there's been a slight burning smell from under the hood... I always thought it was just a little oil on the manifold because it's an old engine and it does leak.

I check the oil level every time I get gas. Four days ago I checked and it was at the bottom of the stick, so I put a half quart in, bringing it back up almost to the full line. Today I was driving and it had a particularly bad hesitating spell. Immediately after that, sitting at a stop sign I noticed wisps of smoke coming out the sides of the hood. The temp gauge was fine and I turned on the heat and it worked. I got scared and pulled over and popped the hood. There was smoke (not tons but definitely visible) coming out from somewhere near the back of the #3 intake runner, I really couldn't tell where though. It looked and smelled like it could have been burning oil or exhaust. I checked the oil again and it was a quart and a half low, all since four days ago (it's never gone that fast before).

It seems to me that it's leaking oil out of somewhere important in the engine and burning it under the hood. When it's cold there's a lot of exhaust but it's always grey, never blue. There are stains on my parking spot but not a quart and a half worth.

jnorion · Post by **jnorion** » Thu Feb 08, 2007 7:18 pm

Day before yesterday I changed out the temp sensor again, using the OEM part this time. Still no change. Then I checked codes again and discovered that my junkyard MAF had tripped all the sensors, so I swapped the old one back in. Doug Vincent showed me how to test it to see if it's still working, and everything is fine on that end.

Yesterday out of nowhere it started running perfectly, and stayed perfect from 1:00pm till about 7:30, then went back to running like crap. WTF?

So it's not the MAF sensor, and it's not the coolant temp sensor. Although even now the #21 trouble code, for the coolant temp sensor, hasn't gone away. I have a hard time believing I've gotten two brand new faulty sensors in a row... maybe the harness is bad?

scuzzy · Post by **scuzzy** » Fri Feb 09, 2007 6:46 am

jnorion wrote:Day before yesterday I changed out the temp sensor again, using the OEM part this time. Still no change. Then I checked codes again and discovered that my junkyard MAF had tripped all the sensors, so I swapped the old one back in. Doug Vincent showed me how to test it to see if it's still working, and everything is fine on that end.

Yesterday out of nowhere it started running perfectly, and stayed perfect from 1:00pm till about 7:30, then went back to running like crap. WTF?

So it's not the MAF sensor, and it's not the coolant temp sensor. Although even now the #21 trouble code, for the coolant temp sensor, hasn't gone away. I have a hard time believing I've gotten two brand new faulty sensors in a row... maybe the harness is bad?

Chances are your harness is good and your knock sensor is faulty, which will explain the missing and related problems/running like shit when hot - if the knock sensor is fractured it won't work properly; and since heat expands metal, this would increase the fracture gap.

It's either your knock sensor or your O2 sensor, if you haven't changed the O2 at a regular interval you need to.

the oil leak is either from your rear main seal or your rear cam seals, both leak pretty bad, you can see the rear cam seals by looking at the back of the head, and looking at which head has more oil on it, if both are clear, then you'll have to separate the block and transmission housing, there's two plates that close off access to the piston wrist pins, those can break and leak, and your rear main seal can leak.

the rear main seal leak isn't serious, usually, I had it on my old engine and I have it on this one, but it is a little work to replace it.

jnorion · Post by **jnorion** » Fri Feb 09, 2007 8:18 am

I think it's probably a head seal... Doug was pointing that out to me when he looked over my engine.

In the last couple of days it's apparently reversed itself, and is now running better when at operating temperature than when it's cold.

I don't even know where the O2 sensor is on this car, but I'll check into changing that... I may as well, I have no idea when it was last done.

jnorion · Post by **jnorion** » Thu Feb 15, 2007 4:25 am

I get the idiot of the month award. I should have started with the basics. I changed the spark plugs and wires today and the problem miraculously fixed itself. Crazy, huh?

douglas vincent · Post by **douglas vincent** » Thu Feb 15, 2007 4:53 am

Dope slap!

jnorion · Post by **jnorion** » Thu Feb 15, 2007 5:58 am

Yes, thanks, I needed that.

Although I took it to a shop and they checked and said the cat IS actually clogged... they checked the temperature and it was reading nearly 50 degrees higher at the front than at the back. Is that a proper accepted way of checking? Either way, they told me that wasn't my big problem and told me not to bother replacing it at this point, but to replace the plugs and wires instead.

musketeerracing · Post by **musketeerracing** » Sat May 05, 2007 7:38 pm

Hey-

I'm having _exactly_ the same problem - sputters on more than about 1/3 throttle, makes a "poof" sound as though backfiring when sputtering, down on power, fine when cold, very lumpy idle, and everything else you describe.

Not throwing a CEL at all, though.

Swapped out the MAF for a thought-to-be-good one, and although it changed the character for 15min or so, it ended up exactly the same.

Did wires and plugs - no change.

Car is stock, but no catalyser.

So...should I be thinking coolant sensor, O2 sensor, ground wire?

How about coil, or vacuum leak?

ACP

jnorion · Post by **jnorion** » Sat May 05, 2007 8:35 pm

All I had to do was change the spark plugs and wires. I neglected to do that when I bought the car last October, I did a half-assed tune up instead.

EDIT: coolant sensor is cheap and easy to replace... may as well do it in case that is the problem.

ericem · Post by **ericem** » Sat May 05, 2007 11:09 pm

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Help me fix my hesitation problem

Help me fix my hesitation problem