Just thought I would lay this out here and see if anyone had any ideas. The car is a 1988 Olds Cutlass Supreme FI V6 2.8L (believe it or not). This car has had a history of idling and hesitation problems. First time this happened, the EGR was replaced and it ran fine afterwards. Second time, the ECM (main computer) was replaced and it ran fine afterwards. Third time, battery was replaced and the dealer said the IAC codes, etc and computer codes were lost ... had to be reprogrammed ... ran fine afterwards (by the way I think this is a bunch of crap). Fourth time, dirty fuel injectors and bore ... cleaned by the dealership ... ran fine afterwards. Only about 20K miles on the car since this was done. Fifth time, changed battery again ... was told that the computer codes, etc might relearn itself and be okay. It did and ran fine after about a week or so. Now it hesitates at about 20 to 35 mph under acceleration. Idle is fine and smooth. Does stumble / idle rough sometimes on startup in the mornings now. Sometimes it dies and has to be restarted. Has died down two times a while back when put in reverse. Car has fairly new Bosch platinum spark plugs and oxygen sensor. Also, the fuel filter has been replaced not too long ago ... AC Delco brand. Air filter is clean ... AC Delco brand. All major tune items have been done ... PCV valve etc. ANY IDEAS???? I am so sick of this car. This happens almost every year now. I went ahead and put in fuel injector cleaner made by Valvoline Syn Power with synthetic cleaners but no results yet. Only about 40 miles since I did that. I'm at a loss of what it could be. Car has about 97K miles. Engine has never been abused or roughly driven. Always good brand of gas is used with 89 or 93 octane (i.e. Chevron or Mobil) Thanks in advance.
CK5
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Hesitation
- Thread starter 87K54WD
- Start date
Burbinator
1/2 ton status
Have you checked any ignition components? Fuel and ignition problems diagnose with almost the same symptoms. I would check the cap, rotor, coil, module and especially the plug WIRES. Sounds like one or more may be arcing, either to ground or each other, or just plain bad. That would be my next step. Hope that helps.
- Alan
'82 K10 Suburban Silverado (AKA U.S.S. Nimitz)
Always do sober what you said you'd do drunk. That will teach you to keep your mouth shut!
- Alan
'82 K10 Suburban Silverado (AKA U.S.S. Nimitz)
Always do sober what you said you'd do drunk. That will teach you to keep your mouth shut!
This engine has the distributor-less system. Does not have the cap, rotor, etc. It has the coil pack deal. Wires have never been replaced, but they still look brand new on the outside. Engine has been kept very clean and spotless. Any other ideas out there?
Burbinator
1/2 ton status
Just because they're clean doesn't mean they're good...ask me how I know. It was just a thought, but run the motor with the lights off (in the dark) and watch for any errant sparks. Good luck!
- Alan
'82 K10 Suburban Silverado (AKA U.S.S. Nimitz)
Always do sober what you said you'd do drunk. That will teach you to keep your mouth shut!
- Alan
'82 K10 Suburban Silverado (AKA U.S.S. Nimitz)
Always do sober what you said you'd do drunk. That will teach you to keep your mouth shut!
Fierospeeder
Banned
My mom had the same engine but different car. 88 celebrity
Our problem was the ignition module was going out. Its near the starter and a pain in the ass to take it out.
They were about 100 bucks. You can grab a timing light and see if each plug wire is emitting a fire, or bring the module to
a car parts store and they can check it for you. I think nappa or murrays can do it.
Also, the platinums are usually not the best plugs to run on an old EFI cars, normal plugs usually give better performance.
74 VW Beetle
84 Pontiac Fiero
87 Ford Thunderbird Turbo
83 Honda Nighthawk 550
Our problem was the ignition module was going out. Its near the starter and a pain in the ass to take it out.
They were about 100 bucks. You can grab a timing light and see if each plug wire is emitting a fire, or bring the module to
a car parts store and they can check it for you. I think nappa or murrays can do it.
Also, the platinums are usually not the best plugs to run on an old EFI cars, normal plugs usually give better performance.
74 VW Beetle
84 Pontiac Fiero
87 Ford Thunderbird Turbo
83 Honda Nighthawk 550
Pugsley
1/2 ton status
Pull the battery cables, and let it sit for 4 or 5 hours disconnected. Then reconnect it, and start it up - let it idle for 45 minutes to an hour, don't touch the lights, throttle, or anything else. This will reprogram the computer at home, for free. See if there's any improvement, and we'll go from there
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Special thanks to those lost from IAFF Locals 94 and 854 - You shall never be forgotten
<a target="_blank" href=http://pugsley.alloffroad.com>pugsley.alloffroad.com</a>
Burbinator
1/2 ton status
Good idea, Pugs...no sense paying a dealer to do that exact thing.
- Alan
'82 K10 Suburban Silverado (AKA U.S.S. Nimitz)
Always do sober what you said you'd do drunk. That will teach you to keep your mouth shut!
- Alan
'82 K10 Suburban Silverado (AKA U.S.S. Nimitz)
Always do sober what you said you'd do drunk. That will teach you to keep your mouth shut!
I'll give that a shot and see what happens. I hope it doesn't get worse. Why so long on the battery disconnect? Wouldn't the memory be wiped out immediately after unhooking the battery? Thanks for the idea. I hope it works. This is just crazy. I've never seen a car so sensitive when changing a battery. My Chevy trucks and Camaro don't have this problem. Go figure. I'll let you know how it turns out. Is this really how the dealership does it? I thought they hook it up to a computer and reprogram the codes, ranges, etc.
Well, it didn't work. I finally got a chance to do what you suggested. Any other ideas? It runs great after say 30 mph. No problems on the highway. It is just the stop n go driving. What do you think about the IAC (idle air control)?
Josh
Registered Member
This sounds similar to the post from Muddin about her camero. Look at my post in there. Also, quit putting those F'ing bosch platinum plugs in a GM. For some reason they DO NOT work right in GM's. They also have very brittle insulators and will crack.
Josh
Josh
DMK
1/2 ton status
I agree no boush plugs in gm. ihave heard this from several people.
muddin4fun
3/4 ton status
How's the fuel pump? I replaced the one in my camaro that was having a similar problem and it's been fine since. This was about a week ago.
Peace and stuff
,
Muddin
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Peace and stuff
Muddin
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Re: Hesitation **UPDATE** Another Question
Just wanted to get your ideas on this. I just replaced my fuel pump, strainer, fuel filter, and relay switch. I was having hesitation, stalling, and "no start" problems and the pump was coming on hours after the car was turned off, etc. Before replacement, I was getting a fuel pressure reading of 20 to 22 psi with power only. With engine running, I was getting 28 to 40 psi (un-steady ... needle on the guage was violently going back and forth between the 28 to 40 psi range.) With the replacements, I am now getting 38 to 40 psi at power and 38 psi steady with engine running. My drivability problems are gone but is this reading still too low when referenced with what my Haynes manual says (40 to 47 psi)? I used new AC Delco parts and made sure I got the right parts by cross referencing with a GM dealer, parts store, and AC Delco's website. I'm just hoping I don't have a defective (weak) pump. The driveability problems are gone but just want to see what you think about the psi readings I am getting now after the fix.
Just wanted to get your ideas on this. I just replaced my fuel pump, strainer, fuel filter, and relay switch. I was having hesitation, stalling, and "no start" problems and the pump was coming on hours after the car was turned off, etc. Before replacement, I was getting a fuel pressure reading of 20 to 22 psi with power only. With engine running, I was getting 28 to 40 psi (un-steady ... needle on the guage was violently going back and forth between the 28 to 40 psi range.) With the replacements, I am now getting 38 to 40 psi at power and 38 psi steady with engine running. My drivability problems are gone but is this reading still too low when referenced with what my Haynes manual says (40 to 47 psi)? I used new AC Delco parts and made sure I got the right parts by cross referencing with a GM dealer, parts store, and AC Delco's website. I'm just hoping I don't have a defective (weak) pump. The driveability problems are gone but just want to see what you think about the psi readings I am getting now after the fix.
