1989 Buick Riviera running rough

[Linus]

Hi all! I’m new here and I don’t know a ton about cars but would appreciate any insight. My 1989 Buick Riviera has an issue where the check engine light comes on, and the moment it does, the car starts running really rough and losing power. It used to just happen on the freeway after about ten minutes but it’s starting to happen more frequently during in-town driving. Sometimes I can’t get up a small hill or even go faster than 5 mph. It’s gotten poor gas mileage the whole time I’ve had it. I recently had a Buick tech at a dealership diagnose it, said it needed a new fuel pump so i got that replaced and it’s still having all the same problems. The error code is always the same: E044. I have had the O2 sensor replaced. Without knowing much, my intuition tells me it’s a weird connection somewhere, as it happens so suddenly. There will be kind of a clunk or jerk feeling and then the service engine light, and immediate power loss and struggle. If i restart the engine it’s fine for a little while. Other clues: today I experimented with not using the AC, which I always do because I live in Tucson. It ran fine except for a little hesitation here and there. I have a feeling it has to do with wiring and heat. Like, on the highway some component could be heating up and causing a short? Or now with the in-town driving in 110 degrees with the addition of the AC running, maybe that could be the culprit? Appreciate any ideas, thanks!

 

[Linus]

Hi all! I’m new here and I don’t know a ton about cars but would appreciate any insight. My 1989 Buick Riviera has an issue where the check engine light comes on, and the moment it does, the car starts running really rough and losing power. It used to just happen on the freeway after about ten minutes but it’s starting to happen more frequently during in-town driving. Sometimes I can’t get up a small hill or even go faster than 5 mph. It’s gotten poor gas mileage the whole time I’ve had it. I recently had a Buick tech at a dealership diagnose it, said it needed a new fuel pump so i got that replaced and it’s still having all the same problems. The error code is always the same: E044. I have had the O2 sensor replaced. Without knowing much, my intuition tells me it’s a weird connection somewhere, as it happens so suddenly. There will be kind of a clunk or jerk feeling and then the service engine light, and immediate power loss and struggle. If i restart the engine it’s fine for a little while. Other clues: today I experimented with not using the AC, which I always do because I live in Tucson. It ran fine except for a little hesitation here and there. I have a feeling it has to do with wiring and heat. Like, on the highway some component could be heating up and causing a short? Or now with the in-town driving in 110 degrees with the addition of the AC running, maybe that could be the culprit? Appreciate any ideas, thanks!

Some more stuff I just thought of: it has a hard time starting. After firing up, the idle drops so low it quits. I have to hit the gas to keep it on, and then the idle goes from as low as 375 to 1200, going up and down. Sometimes the car drives poorly even without the check engine light coming on. It just sort of chugs along slowly, really stuttering, until a sudden surge will kick in and it drives really powerfully for a little while. Then power drops again, back and forth.

 

[MelsRegal]

You didn't go back to the dealer to tell them the problem is still there?
Did they replace the pump?
Code 44 could be the oxygen sensor.

GM Code 44 Lean Exhaust - FreeAutoMechanic

Trouble Code 44 indicates that the O2 sensor is showing a persistently high exhaust oxygen content (lean), despite the efforts of the ECM to increase injector

www.freeautomechanic.com

 

[LARRY70GS]

Unfortunately, you are stuck with On Board Diagnostic 1 technology. Extremely limited compared to OBD2 (1996-present). Your engine has a Mass Air Flow Sensor. It might be helpful to clean or replace it. It tells the Computer how much air is entering the throttle body. The computer uses that to set up the fuel injector pulse. With OBD2, you can read the sensor values with an inexpensive scan tool. Not so with OBD1. The Dealer has a more expensive scan tool that can read those sensor values and see where the problem lies. The fuel pump should not have been replaced unless there was a fuel pressure problem. Even if there was, the problem could be a fuel pressure regulator. What you need is a good mechanic who can test and evaluate results, and not simply be a parts changer. You may have to pay for that.

 

[Zulu Kono]

Start with unplugging the MAF sensor.
If the performance improves, that sensor likely needs to be
replaced, and you could do it yourself with only a screwdriver.

If that has no effect, you need to check the coil packs.
Super easy to do, but you need some gloves to do it.
If the coils check out, it could be that the ICM under them is bad.
Sometimes if the ICM is bad it can make one of the
coils not fire and it will seem like it's a bad coil pack,
when in fact it's a fried ICM.

 

[Linus]

Thank you so much, I’ll look into this!!

 

[ezbersom]

Thank you so much, I’ll look into this!!

did you ever get it figured out ?

 

[Amanda Hugenkiss]

An old thread but just chiming in, symptoms like this sounds like an EGR (if it has one) or a vacuum leak. EGR can be where the valve sticks open, even intermittently, letting too much exhaust in, causing stalling, rough running, and lean codes. Also vacuum leaks, where a line has a crack and if the engine moves the crack opens, causing unmetered air and a lean condition. The tech who just fired the parts cannon at the fuel pump should have known better, it's very simple to test the pump pressure.