olds 3.8l engine stumbling, running rough- any help out there?

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- Robbie Wilson
  
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posted
20 years ago

Mon, Feb 9, 2004 4:23 PM

The engine is the 3.8L V6 in an 87 Ciera Brougham, Auto Transmission, fuel injected 86k miles (my great-aunts old car- thus the low mileage) Originally the car would cut off when mildly accelerating at around

20-30 mph. The camshaft position sensor was replaced as a possible remedy. Now the car will run, but it seems to miss badly around 30 mph or so. The car will get up to a respectable speed (60mph or so) but continues to stumble at various speeds. The error codes were retreived by shorting the A and B pins in the datalink terminal. Retrieved codes: 32- EGR circuit on fuel injected models and 24- Vehicle Speed Sensor or circuit. According to the (admittedly un-thorough) Haynes manual the VSS only controls the torque converter. The EGR valve will function but it is getting no vacuum through the EGR vacuum solenoid (small rectangular box with a vacuum inlet and outlet, a 4 plug connector, and a small tiny air filter mounted on it) Anyone worked on this engine before? Any pros out there? PS- Checked fuel pressure

-30PSI on the fuel delivery rail. Thanks so much! Robert Wilson

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- meg
  
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posted
20 years ago

Wed, Feb 18, 2004 9:21 PM

Barry, I have an 86 Buick Lesabre that has the same problems that you are having. Wondered if you had any luck yet.

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- Joseph Oberlander
  
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posted
20 years ago

Thu, Feb 19, 2004 4:24 AM

I have a 1987 LeSabre. IIRC, the engines are identical. I'd suspect the MAF, fuel pump, EGR system, or timing system.

If it's running rough at an idle, but otherwise runs fine - sort of a wobbling rpm at idle, that's the fuel pump. If you can hear it whining or at all at highway speed, it's wearing out. Mine makes a very loud racket - probably has 10K left on it or less.

If it runs really rough but is fine after a few miles or if you let it run until warm and then turn it off and on - and then it is fine, it's the EGR/recirculation system - basically like having the choke on all the time.

If it runs fine at idle when warmed up, but then is a mess when you try to acclerate(virtually no power), it's most likely the MAF or computer that are having problems.

Timing is something that should be addressed for that year in any case, unless it was serviced at least once before. The stock timing chain is likely stretched half and inch or more and several of the nylon/synthetic teeth on the main cog are likely worn to nubs. Mine had 2-3 teeth left and the computer could only compensate so much.