OptimistPrime
Buick Newbie
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- Buick Ownership
- Buick
I've got a problem with my 92 Lesabre that I just can't pin down. The car drives great, perfectly, for about 60 miles. Then it starts to have no acceleration. Step on the pedal and nothing happens. The only way to get it to accelerate is to feather the gas pedal, but even then the problem gets steadily worse, until the car barely drives at all. For example, I recently drove to a town 50 miles away. Car was great on the way. It sat for a couple hours while I performed the work I was contracted to do. Then on the way back, it malfunctioned about half way home. I know it's not a fluke because the car has done this before several times when I drive it that cumulative distance. I had previously thought it was the ignition control module, but I just put two new ones in and it still does the same thing, after 60+ miles. I have made a topic here before and the general consensus was bad ICM. I replaced it and the car seemed to drive better, but what I didn't know then was the distance the car predictably goes before it breaks. I thought I had fixed it, but really I just didn't have a reason to drive the car long enough for it to mess up again. I'm fairly certain the ICM is fine.
I took it to a local shop and they turned me away, saying they don't have time to drive the car enough to get it in the problem state. And that even if they did, it would be too hot to work on. I guess this car's fate rests only in my hands now. It's only got 76k miles on it so I'm keen to find out what's wrong. However someone recently rear ended it, and there's a good chance the insurance company will total it. If I let this thing go to the crusher without knowing what was wrong with it, it will always bother me. I really hope someone here has some insight.
Since most vehicle problems are an issue of fuel, air or spark, I began troubleshooting there. We already know it's getting good spark when I crank it, so I guess my next thing to try will be getting the car to its problem state and then testing spark to see if there's any difference. I have a feeling the spark is a dead end though. It's got new plugs, coils and a new ICM. I even tried a set of MSD coils but they made no difference.
Ruling out spark, we now have air and fuel. I think the air is fine because the filter is clean and the MAF sensor is fairly new. Plus, the car hasn't done any of the stalling it did when the MAF previously went out. Even in the worst of its problem state, it never stalls or acts like it's close to stalling. The guy at the shop who turned me away was pretty sure it was the cat, but I've previously had it tested and it was fine. Perhaps the cat only clogs up when it's super duper hot. Like the honeycomb inside is busted up and flapping around? I heard of that happening on some guy's truck before. A piece would flap down over the exit hole when the cat heated up. Since this car no longer needs emission tests I could just delete the cat. But I'd like to be sure before doing that.
The final possibility is fuel. I only bring it up because the car's problem state seems very similar to how it behaves when I have a low tank of gas and take a tight turn. Then all the gas sloshes to one side and starves the fuel pump for a couple seconds. The car struggles to accelerate. It happens only when I'm nearly out of gas, unlike the other problem which happens even with a full tank. Bad fuel filter maybe? But the car runs flawlessly when it's cranked. No sputtering even in its problem state.
I don't think it's an issue being detected by the computer, because there's no warning lights and the cruise control works fine. When this car previously had a check engine light on from a bad throttle position sensor, the cruise control wouldn't work. The other day when the car was malfunctioning, I tried the cruise control and found it had no problems at all maintaining speed. Transmission seems fine, and even when the car won't accelerate well it still will shift gears fine. Usually the car idles great, even in the problem state. However, sometimes on warm start, it will trundle like a dump truck. That doesn't mean it's about to malfunction, though. I just give it a few revs and it calms down. Bad cam or crank pos sensor perhaps? I wonder if a bad one of those sensors would act up more after being super heated.
Sorry for the long-winded post, but I'm just trying to get down everything I can think of about this problem. If anyone has any ideas I'd love to hear them.
I took it to a local shop and they turned me away, saying they don't have time to drive the car enough to get it in the problem state. And that even if they did, it would be too hot to work on. I guess this car's fate rests only in my hands now. It's only got 76k miles on it so I'm keen to find out what's wrong. However someone recently rear ended it, and there's a good chance the insurance company will total it. If I let this thing go to the crusher without knowing what was wrong with it, it will always bother me. I really hope someone here has some insight.
Since most vehicle problems are an issue of fuel, air or spark, I began troubleshooting there. We already know it's getting good spark when I crank it, so I guess my next thing to try will be getting the car to its problem state and then testing spark to see if there's any difference. I have a feeling the spark is a dead end though. It's got new plugs, coils and a new ICM. I even tried a set of MSD coils but they made no difference.
Ruling out spark, we now have air and fuel. I think the air is fine because the filter is clean and the MAF sensor is fairly new. Plus, the car hasn't done any of the stalling it did when the MAF previously went out. Even in the worst of its problem state, it never stalls or acts like it's close to stalling. The guy at the shop who turned me away was pretty sure it was the cat, but I've previously had it tested and it was fine. Perhaps the cat only clogs up when it's super duper hot. Like the honeycomb inside is busted up and flapping around? I heard of that happening on some guy's truck before. A piece would flap down over the exit hole when the cat heated up. Since this car no longer needs emission tests I could just delete the cat. But I'd like to be sure before doing that.
The final possibility is fuel. I only bring it up because the car's problem state seems very similar to how it behaves when I have a low tank of gas and take a tight turn. Then all the gas sloshes to one side and starves the fuel pump for a couple seconds. The car struggles to accelerate. It happens only when I'm nearly out of gas, unlike the other problem which happens even with a full tank. Bad fuel filter maybe? But the car runs flawlessly when it's cranked. No sputtering even in its problem state.
I don't think it's an issue being detected by the computer, because there's no warning lights and the cruise control works fine. When this car previously had a check engine light on from a bad throttle position sensor, the cruise control wouldn't work. The other day when the car was malfunctioning, I tried the cruise control and found it had no problems at all maintaining speed. Transmission seems fine, and even when the car won't accelerate well it still will shift gears fine. Usually the car idles great, even in the problem state. However, sometimes on warm start, it will trundle like a dump truck. That doesn't mean it's about to malfunction, though. I just give it a few revs and it calms down. Bad cam or crank pos sensor perhaps? I wonder if a bad one of those sensors would act up more after being super heated.
Sorry for the long-winded post, but I'm just trying to get down everything I can think of about this problem. If anyone has any ideas I'd love to hear them.