Buick Park Avenue hesitating/missing under hard acceleration
I have a 2002 Buick Park Avenue with 140,000 miles on it. The car has always
run beautifully until a few days ago when it started hesitating and missing
under hard acceleration on a warm engine. Under light and normal
acceleration there's no problem at all. At first, this only happened for a split
second at take off from a standstill, but now it hesitates and cuts out all the
way up until the car reaches cruising speed before the problem disappears.
Some things to consider:
--This only happens when the engine is warm. It doesn't happen at all when
the engine is cold.
--Happens in all gears including park (if I'm sitting still and stab the pedal
--The Check Engine light is NOT on.
--The car was recently smog checked and passed (California emissions test),
so the catalytic converter is fine.
--Was just in Mexico with the car on a long trip, had to buy their gasoline,
figured that was the problem, but I've refueled with high-octane U.S. gasoline,
used additives, and the problem continues to get worse.
--Fuel economy is great at 30 MPG, passing on the highway is fine, idles
I'm thinking the problem could be plugs and wires, but I'm not entirely certain.
Any ideas would be appreciated.
Could be the thermostat also
Have Cat checked for partial blockage ,,, I've seen 3 GM's with no codes showing that had your problem, One guy even had his transmission rebuilt. At lower engine speeds a partial restriction probably will go unnoticed but when your pushing lots of exhaust out a partial blockage will choke an engine. Having your back pressure checked is the less costly of all repairs and could save you the most money
Thank you. This is certainly a possibility and I'll have it examined. The problem has gotten worse in the last 24 hours. It's now hesitating at all speeds when the accelerator is depressed, the fuel economy is getting worse, there's a rattling noise under the car when cold and the exhaust has a slight odor I've never smelled before. All signs look like they're pointing the the cat, as you've suggested.
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