RPM drops while accelerating

[mounddog]

Strange problem with my '92 buick park avenue. I was having problems with it cutting out while i was driving, but after replacing ignition module/coils/maf/tps/battery/camshaft and crankshaft sensor (crankshaft sensor seemed to do the trick), the car has stopped cutting out (for now).
I still have a problem ive had for a couple of years. When im driving in the 30-50pm range and steadily accelerating (lightly) i will have a sudden drop in RPM/ and power - i notice it will for example go from 2500 to 2000rpm even though i am pressing on the gas pedal. There is a slight sluggish feeling - and then about 2-3seconds later rpm and power return. Its quite annoying - i dont feel secure driving the car. Anyone have any clues to this? Couple notes: 112k on 3800 engine, did change the headgasket about 1.5 years ago (i first noticed the problem about 3 monthes before the headgasket change). Still has original plug wires, plugs are 1.5 years old. Everything else on car seems to be ok. Thanks!

[aarcuda]

is it shifting into the next higher gear and then back down?

[tman]

I know exactly whats wrong. The plug wires are 12 years old. They wear out easily, I'm surprised they've lasted so long! Replace the plugs, AND wires, and you'll be good to go.

If there still is a problem, I can only think of a tranny problem.

[mounddog]

Thanks - ill try replacing the wires/plugs this weekend - will let you know how it goes. Hope its not the transmission. Mike

[Opps123]

hey, i got the same problem...i have no idea why it would do this...im thinking maybe something is wrong with the 4th gear overdrive or maybe the computer is faulty i dont know im gonna take it to a tranny place and see if they can find the problem...i will check back if i do..

[tman]

the tranny problem I referenced to is a destroyed 4th gear. My cousin towed a trailer with his 91 park ave, and it would mess up in overdrive. he told the sap he sold it to that the D with the circle around it was for driving on a turnpike.

[mounddog]

Well replacing the wires definitely helped the overall performance of the car - but it still has that rpm drop, acceleration hesitation issue. I examined it closer and it seems to mostly happen past 40mph, and i noticed that as im pressing the accelerator, the rpm will drop - and it will sort of 'plateau' at whatever speed its at. It wont Drop speed, just RPM drops, and mph stays there. If i let go of the gas and then press down again it will come back and continue accelerating, with RPM rising. Pretty strange. Opps123 - if you take to the tranny place let me know what they say. Ive got some other issues to deal with rightnow - brakes and now my brakelights/turn signals arent working. You have to have alot of patience with these babies!

[Opps123]

hey, i took it to the trannny place, the tech said i have a bad missfire which just started to happen yesterday (when i took it there) so he said get the misfire fixed that should be 90% of the problem, hopefully they can figure this out...thanks again

[mounddog]

Hi - anyone know what causes this misfire? May be the same problem as mine - as i forgot to mention that when i have the car parked and idling, if i rev it up press hard, it will stay revving strong and then i will hear a Loud pop sound, like i guess a misfire. Maybe this is what happens when i get into the 40mph+ area. I replaced plug wires- plugs are only about 2 years old - any other ideas? Thanks

[Opps123]

my problem with the misfire was my ignition coil one of the cylinders wasnt getting enough spark..i switched out the coil no more misfire but i still have the problem with the rpm dropping i dont know what i could be hopefully nothing too big..thanks see yah

[N55340]

Originally Posted by mounddog

Hi - anyone know what causes this misfire? May be the same problem as mine - as i forgot to mention that when i have the car parked and idling, if i rev it up press hard, it will stay revving strong and then i will hear a Loud pop sound, like i guess a misfire. Maybe this is what happens when i get into the 40mph+ area. I replaced plug wires- plugs are only about 2 years old - any other ideas? Thanks

My 92 has the same problem. My mechanic tried for a month to resolve the problem and finally gave up. He even took it to the local GM shop and they could figure it out either. I would love to know the answer to this one.

[dgogley]

Hi guys I am the owner of a 96 Lesabre Limited which has the same issue, my car is always interstate driven and currently has only 81,000 miles. I have read countless posts reguarding this same issue all over the US and Canada with miles as little as 30,000 however nobody ever seems to post a "fix" or cause of the problem. I have not taken mine into the dealer yet $$$ for a diagnosis. This just seems to be a common problem with Buick and the 3800 engine or is it a design flaw???


HELP!!!

[lglm8]

I had the same thing happen, along with a missing engine when I accelerated, I changed the plugs and wires and now when I push down slowly, the rpms stay the same until I push down more sharply... no drop in rpms at any time, I am thinking some sorta vacuum issue??

[mounddog]

Ive basically got most things on my car fixed - and shes working great now - EXCEPT for this annoying drop in RPM when accelerating issue (more details in below posts). Anyhow know whats up with this? If i could figure this out i could Perhaps meet that Nirvana of actually not having a problem with my baby Buick for a few weeks (wouldnt that be amazing!?). Right now she is driving great - but wish it wouldnt do this hiccup thing as im accelerating. One time i was so frustrated i just crammed the pedal to the metal - and boy did she wake up and Go Fast - i was surprised she oculd have that much kick. But alas the strange drop in RPM issue is still there. I think i might ahve to suck it up and bring it ot a dealer - i like to fix most things myself. At least shes working well enough now that i can use her as my main car and restore my '64 galaxie and not drive that gas hog around. Mike

[Jed Rule]

While holding steady pressure on the gas at 50mph, lightly touch the brake with your left foot. This will dis-engage the Torque Converter Clutch. Note the rpm raises. When you release the brake, the TCC will re-engage. Is this what you are feeling?