Engine stutter under hard acceleration? (searched)

Fkyx · Post by **Fkyx** » Wed Dec 12, 2007 12:51 am

Hi. My roommate and I are stumped by this one. When I'm hard on the gas, the car sort of stutters in and out of power. It's not a consistent type of stutter... here's a video:

http://www.youtube.com/watch?v=GU1lEaa-gPI

It's hard to pick out the stutter -- any time you hear the engine sound "cut out" for a split second and then come back, that's the stutter... not a sound problem.

The kicker is it doesn't do this while the engine is still warming up. It accelerates smoothly, no problem, if it's not at "running temperature". Also, unlike some of the other threads I found in my search, the car doesn't bog down at all at idle. There's no stutter at idle. It runs perfectly until it's warm and I get on the gas hard.

The boost gauge shows a constant 9lbs (that's what I'm running).

I figured this may be related to that carb fuel filter that was sitting after the normal fuel filter, but after deleting that and still being plagued with the problem, I'm more than sure it's unrelated (unless the carb filter damaged something to cause this problem). So I cleared, then checked my codes, and in addition to the 22 and 23 I had before, I now have a code 24 on my hands. The car also smells like it's running rich after deleting the carb filter. I looked into replacing the O2 sensor, and I plan to get around to this in the next week or two unless this stuttering problem makes it unwise to do a 300 mile drive home.

Any thoughts? Sorry about the long winded post.

subieal · Post by **subieal** » Wed Dec 12, 2007 4:12 am

Hey i had a simmalar problem with my car a while back and it started happening as soon as i got rid of the air box and put a high flow cone directly after the MAF. My roomate and myself battled it forever and finally i put cold air in my car and the problem went away so we figuered that having the air filter so close to the MAF causes some funny turbulence making for a weird air flow reading. So if you have a cone filter id try spacing it away from the MAF a little bit and also make sure that the wire inside the MAF is clean. Hope this helps!

asc_up · Post by **asc_up** » Wed Dec 12, 2007 5:57 am

i'm not sure what the problem is, but your car sounds awesome!!

Fkyx · Post by **Fkyx** » Wed Dec 12, 2007 7:37 am

asc_up wrote:i'm not sure what the problem is, but your car sounds awesome!!

Thanks.

That's all the PO's fault, though. I had nothing to do with it... but I did have the balls to make the blind purchase. Here's the exhaust video:

http://www.youtube.com/watch?v=FBvBGz9ZIOA

Steeper · Post by **Steeper** » Wed Dec 12, 2007 8:09 am

my car has a cone bolted directly to the MAF and I know of several other 2.2 turbo and NA that are the same, havent seen any problems from it yet.

ciper · Post by **ciper** » Wed Dec 12, 2007 9:21 am

Have you ever replaced the spark plug wires? Can you get the car in complete darkness and have someone rev it while you watch for sparks?

Fkyx · Post by **Fkyx** » Wed Dec 12, 2007 9:26 am

I can do that. When I look for sparks, I'm assuming they're a bad thing, correct? And if there are sparks I should replace the spark plug wires.

Post by **Legacy777** » Wed Dec 12, 2007 4:33 pm

I'd start with plugs & wires. You may want to take a spray bottle and mist water over the plug wires & coil pack and see if you see any sparks.

subytech · Post by **subytech** » Mon Dec 17, 2007 2:03 am

Steeper wrote:my car has a cone bolted directly to the MAF and I know of several other 2.2 turbo and NA that are the same, havent seen any problems from it yet.

Seems to depend on the car, I've seen some that dont have any problem and some that will bearly run.

evolutionmovement · Post by **evolutionmovement** » Mon Dec 17, 2007 3:06 am

Yeah, it sounds like classic ignition issue. In my experience, these cars eat wires, but a set from Magnecor will probably be the last set you'll need.

Fkyx · Post by **Fkyx** » Mon Dec 17, 2007 3:27 am

I've been looking into wires. Unfortunately, they're rather spendy when I take a look at my financial situation. I'm going to start with *checking* the O2 sensor, then the fuel filter, and if all of that checks out, I'll move toward buying a set of Magnecor wires. I think in the process I'll grab a new set of NGK plugs.

I figured, though, that if it were an ignition problem, it would show all the time, not just under hard acceleration in gear.

biggreen96 · Post by **biggreen96** » Mon Dec 17, 2007 3:50 am

just the other week my car was acting up REALLY bad, misfiring and popping like crazy, I couldn't even get up the hill to my house it was so bad and it finally died and wouldn't restart. I took the cam and crank sensors out and wiped the crap off them (there seemed to be a lot) and it started back up and ran well.

ericem · Post by **ericem** » Mon Dec 17, 2007 5:35 am

Where is the cam and crank sensor??

biggreen96 · Post by **biggreen96** » Mon Dec 17, 2007 5:53 am

cam: right hand side of engine on the head, one bolt holding it on, it gets reading from the cam pulley. very easy to get at.

crank: under and to the left of the alt, above the crank pulley, also one bolt holding it on, also fairly easy to get at.

hope this helps.

Fkyx · Post by **Fkyx** » Tue Dec 18, 2007 6:44 am

I took the O2 sensor out and cleaned it today. That didn't fix the problem, AND it's still running rich! (hoping I don't have to replace it all together) I'm going to go ahead and replace the fuel filter tomorrow, and if that doesn't fix the stutter, I'll order myself some new Magnacore cables.

If the car is running a Walbro 255LPH pump, but is still on the stock ECU, would that cause it to run rich?

evolutionmovement · Post by **evolutionmovement** » Tue Dec 18, 2007 4:05 pm

If the fuel filter was bad it wouldn't be running rich.

Fkyx · Post by **Fkyx** » Tue Dec 18, 2007 5:00 pm

Alright. I'll see if there's a place around town that stocks the Magnecors and replace those.

dzx · Post by **dzx** » Thu Dec 20, 2007 2:53 am

It's possible your timing jumped a tooth.

Boostedballs · Post by **Boostedballs** » Sat Feb 16, 2008 10:20 pm

Any updates on this? I have the same issue with my 91 turbo. My car is bone stock and no mods to anything but a K&N filter.

I've replaced the:
fuel filter, plugs, air filter, PCV valve.

The problem still exists if I disconnect the:
O2 sensor, knock sensor

I'm starting to think the cats must be clogged or the plug wires are shot.

PS: (from earlier reply about plug wires failing) The plug requires more voltage to jump the gap as pressure increases. Sort of reverse logic, but that's the way it is.

not trying to hijack, just trying to revive the thread...

what huh · Post by **what huh** » Sat Feb 16, 2008 10:30 pm

i had this problem with my 98 GT-T i replaced the air filter, plugs and wires. And it helped a little but the problem was still bugging me. Then i had to replace the fuel filter and then i was running very rich causing the same problem but worse. And then i got it retuned and it ran like i never thought it would. It was awesome but dealing with the problem did suck. So i would recomend replacing your fuel filter also.

livestrong14 · Post by **livestrong14** » Sun Feb 17, 2008 2:14 am

Plugs, Wires, check all vaccum lines, and all of your IC clamps. Especially look at your TMIC to Throttle Body clamp.

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Engine stutter under hard acceleration? (searched)

Engine stutter under hard acceleration? (searched)

stuttering car