1996 Park Avenue 3.8 L Bucking and Hesitating

[digitalsaw]

I need some assistance with a hestiation problem I am having with my 96 Park Avenue. Here are the facts.
I own a 1996 Park Avenue 3.8 V-6 with 104,000 miles. The problem is a bucking and hesitating when it warms up. Cold it runs great. When it is warm it begins to hesitate (at all speeds) when the accellerator is pushed s-l-o-w-l-y. It bucks and acts like it is kicking in and out. A typical example is rolling down a flat stretch of road at 65 mph with the cruise on. Here comes a small hill. As the vehicle begins going up the hill the cruise automatically tries to accellerate the engine to compensate for the hill. It begins to buck hard. I put my foot on the accellerator and can accellerate through the bucking and it smooths out. A few more facts.
- Problem ONLY happens when it warms up. Typicall this may be as much as 10 miles down the road.
- When it gets fully warm it will hesitate slightly taking off from a stop light. Again, just small short hesitations. Even putting your foot into the accellerator it will not totally smooth it out when it is fullly warmed up.
- I have replaced all of the ignition coils, and the ignition module below the coils.
- I replaced the plugs and wires about 7 months ago. I did NOT replace with AC Delco wires.
- When I posted this forum before a few people told me they think it was the plug wires. Before I spend another $80 on wires can someone give me any idea what could be causing this problem? I would appreciate any advice.

[tman]

$80???? I can get my Delco wires for $35!!!!!!

[digitalsaw]

I wish I could find them for that much. I have been quoted about $60, I was including plugs with the $80 price. Regardless, any ideas or does everyone just think I should go with wires first?

[tman]

I'd say wires, become friends with a parts department guy at a dealer, and have them charge you wholesale, as if you were an auto repair company.

[Don Gwinn]

When mom had this problem with her '95 (which I'm about to buy) it turned out to be the transmission. It was a bear; we've got a great trans guy here locally, Herb, and we took it to him when the dealership couldn't figure it out (their solution was to replace the CPU, then throw up their hands.)

Herb was sure it was the transmission, but couldn't find the problem. So he pulled it and put in a rebuilt unit, which left her with exactly the same problem. So we took it back and Herb tried everything he could think of--again. He was still convinced it was the transmission hunting a gear (it always happened between 45 and 65 mph, it seemed.) Eventually he took the old transmission (which he had since rebuilt as well) and put it back in. Now the problem disappeared!

Turns out the original transmission had a tiny, freak pinhole in a valve body, probably from casting sand or something. The crazy thing was that the replacement piece had the same hole in precisely the same place, which explained why it didn't fix anything.

Herb charged mom the price of the rebuild parts and the labor he'd have charged for the original rebuilding, which was about a sixth of the labor he actually put in. We're all going to be using Herb for a long time.

[lglm8]

fixed problem by changing plugs and wires ( had bad wire, fell apart when removing ( supposedly replaced 30k ago).