Intermittent hesitation when cold - 1995 Olds 88 3.8L

The service techs who work on my car are pulling their hair out over the problem - a very intermittent hesitation when the car is first driven.
The car is a 1995 Olds 88 with the 3.8L engine with just over 75,000 miles
on it. A couple of months ago it developed an occasional hesitation while first driven, or sometimes a rough idle before I back it out of the driveway. Won't do it on a regular basis; the car might run fine for several days, and then the problem occurs. Usually it only lasts for 10 - 15 seconds close to home, although it did act up once while stopped in traffic about a mile from home - it felt like the engine was going to die, but kept chugging. Not much happened when I stepped on the gas, but after about 20 seconds the idle smoothed out and I could accelerate. Car went to the garage after that incident, and the techs have encountered the problem, but are still trying to figure out the cause. Oh and one time while the car was misbehaving in the driveway, I popped the hood, in case I could see anything. While the idle was going up and down, I did hear a loud mechanical snap, and the idle smoothed right out.
Here's what has been checked, so far: no check engine light when the car hesitates, and no trouble codes stored. They suspected a fuel pump problem, however, they did get the car to fail with a pressure gauge hooked up, and eliminated a fuel problem from the pump. Possible electrical ground problem, but that didn't solve it either.
They did give the car a tune up; they said the wires looked a bit old, although they were (supposedly) changed back in 2001 around 55,000 miles by an Olds dealership that I stopped doing business with.
Anyone have any thoughts or ideas on this? I'd welcome suggestions on this, since the techs have had the car for several weeks, and would love to get it back to me. I understand intermittent problems are hard to track down; I've had experience in the computer and electronics repair industry so I'm giving them as much time as it takes to find the problem.
Thanks for any input. Bob.
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That's funny, I am currently having the same problem with my '95 Monte, but it's a little less intermittent. I think it's the PCM or the fuel pump wiring on my car.
Steve

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Steve Mackie wrote:

On mine it was the EGR valve(or whetever equivalent system your 95 has) and the MAF both dying a slow death. Also, the timing gear should be inspected, it's notoriously weak and needs to be looked at just like a belt on these engines. Leaving it to 130-150K will cost you a lot of money.
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"Bob" wrote:
1995 Olds 88 3.8L Intermittent hesitation when cold.
....occasional hesitation while first driven......sometimes rough idle before backing out of driveway.......usually only lasts for 10 - 15 seconds.....once started chugging while stopped in traffic.....after about 20 seconds the idle smoothed out and I could accelerate... once there was a loud mechanical snap, and the idle smoothed out.
Any thoughts or ideas? _________________________________________________________
We had similar symptoms with our 1992 Buick 5.7L. It was the Idle Air Control valve intermittently sticking. We did not replace it - just exercised it manually, cleaned off the pintle valve and the valve seat in the throttle body and reinstalled it. No trouble since. HTH.
Good luck.
Wendy & John. _________________________________________________________
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Does it do this only within a few minutes after starting, or does it also happen when the engine is warmed up?
If it happens only after start-up, it could be the Mass AirFlow sensor. I have a 1993 Olds 88 that would start and run fine EXCEPT when given more than half throttle. It would act like this until the coolant temp went over 100 degrees, at which point it would run better. Also, the engine would ping under heavy load unless I used hi-test. After manually testing the TPS and MAF with a VOM (I'm still a DIY mechanic), the results clearly indicated the MAF was bad. After replacing it, it has run great. Good luck.
doug

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Oh - take it to the dealer. They have the computers and modules to swap in do track down problems on hand, plus real computers instead of the cheap generic ones. Three machanics were clueless on mine and then I took it to the GM garage. 1 hour to diagnose right, and what was three weeks DOA was fixed and running by that afternoon.
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Joseph Oberlander wrote:

Joseph,
I would, except I've had some bad experiences with two different Olds dealers in regards to service. The last straw was several thousand dollars of repairs on the A/C, only to have it go flat a year later. Took it to my local service station, and the evac and recharge they did has held up fine. Oh, they do come highly rated, and have been very honest to work with, unlike my experience with the dealers.
I do appreciate your feedback and answers.
Bob.
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doug wrote:

Doug,
So far, it's happened right from a cold startup, or after driving a very short distance, say 1 or 2 city blocks. Once it was after being driven about a mile, again from a cold start.
Seems to run fine after the car reaches operating temperature. Thanks for the input; I'll pass it along.
Bob.
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Many thanks to all who responded; I'll post back with the fix, once they get to the bottom of the hesitation problem.
Bob.
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"Bob152" wrote: > The service techs who work on my car are pulling their hair > out over the > problem - a very intermittent hesitation when the car is first > driven. > > The car is a 1995 Olds 88 with the 3.8L engine with just over > 75,000 miles > on it. A couple of months ago it developed an occasional > hesitation while > first driven, or sometimes a rough idle before I back it out > of the > driveway. Won't do it on a regular basis; the car might run > fine for > several days, and then the problem occurs. Usually it only > lasts for 10 - > 15 seconds close to home, although it did act up once while > stopped in > traffic about a mile from home - it felt like the engine was > going to die, > but kept chugging. Not much happened when I stepped on the > gas, but after > about 20 seconds the idle smoothed out and I could accelerate. > Car went to > the garage after that incident, and the techs have encountered > the problem, > but are still trying to figure out the cause. Oh and one time > while the car > was misbehaving in the driveway, I popped the hood, in case I > could see > anything. While the idle was going up and down, I did hear a > loud > mechanical snap, and the idle smoothed right out. > > Here's what has been checked, so far: no check engine light > when the car > hesitates, and no trouble codes stored. They suspected a fuel > pump problem, > however, they did get the car to fail with a pressure gauge > hooked up, and > eliminated a fuel problem from the pump. Possible electrical > ground > problem, but that didn't solve it either. > > They did give the car a tune up; they said the wires looked a > bit old, > although they were (supposedly) changed back in 2001 around > 55,000 miles by > an Olds dealership that I stopped doing business with. > > Anyone have any thoughts or ideas on this? I'd welcome > suggestions on this, > since the techs have had the car for several weeks, and would > love to get it > back to me. I understand intermittent problems are hard to > track down; I've > had experience in the computer and electronics repair industry > so I'm giving > them as much time as it takes to find the problem. > > Thanks for any input. > Bob.
I have the same issue with my 1995 Olds 88. I have found that any mechanic is willing to take your money to TRY and fix it. The problem is that it is an intermittant one. I was going down the fuel pump route as well. One mechanic said it checked out fine, but it is intermittant so if he reconnected the OK fuel pump it should still run bad... ...no, its intermittant. One piece of new information. With a tank of fuel on the low side, while exiting a Highway on a cloverleaf right ramp, the car will chug as you describe. If parked on a decline with the same low tank it too will chug and die as you describe. If you take several short trips and park at any level it is bound to chug on startup and die as well. I truely believe it is a fuel delivery issue just have not isolated it yet. Anyone who sits there and scratches their brain and claims to know what it is such as ignition module, fuel pump for sure, wires, ... ...without experiencing it first hand does not know what they are talking about. Please let me know if these additional symptoms are true for your car as well.
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djm2 wrote:

The mechanics eliminated the fuel pump when they were able to get the hesitation / chugging to occur while they had a fuel pressure gauge hooked up to the car, and the pressure remained constant while the car acted up.
On my car, once it's fully warmed up, it runs fine without any problems. In only seems to occur from a cold start, and the first few miles as the car warms up to operating temperature. Sometimes. It's acted up with a full to 1/4 full tank of gas - level doesn't seem to matter.
So far, the car has had a tune up (which it was going to need anyway); they found a cracked crankshaft sensor, and swapped out the ignition module. I took it home on a Friday evening where it acted up within two blocks. Took it for a long drive, parked it, and did a short run on Saturday. Did lots of chugging / hesitating while driving down the street. Did another run on Sunday, it did it's surging bit in the garage, then smoothed out, and ran fine. It was back at the garage on Monday. I might stop in and see what the status is today. Oddly enough, after they changed the crankshaft sensor and ignition module, it seemed to be acting up more often, at least the couple of days I drove it over the weekend.
With your car, it sure sounds like a fuel pump / fuel delivery problem. Wild guess - maybe a clogged filter within the fuel tank; I think there is a sock like filter around the fuel pump to pre-filter the gas going to the pump, and yours might be full of something. Then again, I'm no mechanic.
One thing with my mechanics, so far, I have not received a bill for the work done. They truly want to find the actual cause of the problem, and not just toss parts at the car, hoping one will fix it. I am going to pay for the tune up (which it needed) and the crankshaft sensor, since that's been a failure item on GM cars. Sounds like the original ignition module will be put back, since the new one didn't fix the problem.
Thanks for the info, and what ever the resolution turns out to be, I'll post it here.
Bob.
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Bob wrote:

This is likely an aging MAF and/or EGR valve(IIRC, the 3.8s use them) I replaced both and my car came alive - easily 30% more power and no more problems stalling at idle. The EGR basically is like a choke on a bike, so if it's massed up, you stall at lights, idle poorly, etc. The MAF(and 02 sensor) - that would create the surging and bogging while driving.
Try this - step on the accelerator quickly. Okay, slam it hard. :) What happens - does the engine rev hard like it should? The MAF, even if half-dead still understands full-open throttle. It's the inbetweens and trying to make small changes that make it confused in a dying state.
Both dead together results in a nearly undriveable mess, btw.
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The loud mechanical snap you heard as the engine smoothed out would suggest a stuck EGR valve, however from 1988 on they used digital ones and hence there is diagnostic capacity for its function (a check-engine light and/or set code when it's malfunctioning). Similarly, any sensor out of range would (should) give you a check engine light, which you don't have. When there's a malfunction with no codes I'm always looking at the fuel system, at least to begin with. Could that noise have been something to do with the fuel pressure regulator somehow sticking? That's kind of a stretch I know, but it's not going to be something normal at this point. Incidentally, I had a mind-blower problem with my 2.8 multiport, it acted up periodically with no codes, problem turned out to be the ECM itself (hence no codes). Ain't it fun?
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James Goforth wrote:

It's looking like the problem was either with the ECM, the coil pack, or a bad electrical grounds. The service station shot-gunned those three items, and gave the car back to me when I needed to make an emergency road trip, and I didn't trust my beater second car for the long distance trip. No stalling or hesitation after those three items were replaced or worked on, plus I did get really good gas mileage on the trip.
The car is back with the mechanics; they are going to swap back the ECM and/or coil pack with my original ones, to determine what really was causing the problem with the intermittent hesitation with no trouble codes. I'm leaning towards the ECM as the cause of the problems, but it might be the coils, or a real funky problem with an electrical ground. Plus they did try a couple other modules (ignition & PCM(?)) that didn't fix the problem, so I'll get my original ones back as well.
I'll post back with the final solution once I get the car back.
Bob.
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If anyone is still following this old thread on my '95 Olds 88, the mechanics did verify the problem was with the ECM causing the intermittant hesitation and no codes being set. No idea what the final cost will be, but the car did get a full tuneup, along with the techs finding a cracked crankshaft position sensor.
Bob.
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