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I bought this car in 1999 when it had 84,000 miles on it. Soon after, i noticed a 'surging' during accelerating, especially uphill. Later the 'check engine. light came on intermitttently. My mechanic could find no codes, so he changed the plugs/wires, with no effect. Today, it has 123,000 miles on the clock, and exhibits the following symptoms: 'check engine light on at all times, still intermittent surging on acceleration, boost occasionally and innapropriately limited to 5 psi, occasional backfiring under hood (usually when shifting into 2nd gear as I accelerate, or upon sudden heavy acceleration without shifting). It has become particularly difficult to start out on a hill, requiring higher rpms as the clutch is engaged, to prevent the engine from stumbling. It has always felt weak around 1700 rpm in 2nd gear. It floods intermittently when trying to start, but normally starts right away. Always starts after flooding by holding gas pedal to floor, with varying amounts of smoke clouds and sputtering. Very rarely, while accelerating, the engine seems to cut out entirely (though only momentarily-long enough to throw me forward in my seat). None of this is affected by weather, ambient temperature, or engine temperature. My mechanic could pull no codes early on, but most recently, he got codes for at least 7 different engine sensors, leading him to suspect the ECU. Any ideas or experience with similar problems out there? The timing belt was replaced at about 90,000 miles, and other than normal maintenance, I do not believe the engine has ever been worked on-I purchased from the origianal owner with receipts. There are no mods.

Number one thing, you shouldn't be driving that car around in the condition it's in. That's probably why there's a ton of codes.

Here's what you should do. Reset the ECU, which can be done by using the instructions on my site, or by pulling fuse 16 for 10 min. Drive the car around the block, or until the CEL comes on again. Go back home, use the instructions on my site to pull the codes from the ECU. Once you have the codes, let us know what you find.

I'd be willing to bet you have a loose or cracked air tube. I had the same symptoms briefly a few years ago and that's what I found. You know, all those 1/4" black soft tubes, what's the technical name for them, Josh?

Jim

not sure.....which tube, where's it at?

Do you mean vacuum lines?

Also check the Mass Air Flow unit. I had repeated problems on my GL-10 because of that unit. The problems sound very similar to mine, although yours are a little worse. I especially had problems going up hill like you said.
Problem is I dnn't know how to test that unit and it is costly to replace. Anyone know how to test it?

I'd definately follow Josh's advice first though.


-Ryan

mikec wrote:Do you mean vacuum lines?

Yes, thank you. And they are hard to spot when they are loose, so even that much harder to spot when cracked or otherwise failed I would imagine.

Jim

From your comments it sounds like you already have a boost gauge hooked up to the car... How much vacuum are you getting at idle and when decelerating in gear. If this is not around 19-20 (in/hg?) then that would tell you about a bad vacuum leak. And if the car keeps running off wastegate boost, this is most likely related to the CEL. My car did this for a day, I don't know what code tripped but when the light was on the car was running off the wastegate (and slow, what's 3 lbs of boost here and there?).

Thanks. I forgot to mention my mechanic could not clear the codes. He is a competent mechanic. This has gone on for a while only because he does not want to just start replacing parts, and I told him I would hold off until it really bothered me to drive it. It has gotten to that point. Still, it runs well most of the time. The cutout problem has happened only 2-3 times in the last 6 or more months. I'll try to find some time this weekend to use your advice.