Since our recent heat wave here in Michigan...my 2000 Grand Prix GT 3800 with 200,000 miles has been acting strange
I drive 60 miles after work each afternoon to the gym I hit on the way home.
Trip is all highway from work to gym.
I park the car, work out, and return to start the car and head home about an hour later.
When I start the car to head home. It starts hard, takes a bit longer than usual to fire, chugs, bogs, then idles slowly for 5-10 seconds. Stumbling clears then engine REVS way too high. Gets up to 3,000 rpms. I try to give a little throttle and RPMs just increase and stay there.
The more I add throttle the higher it reves and stays/sticks.
Shut down 2 or 3 times and slowly starts to get better and return to normal.
???
Air temps have recently went from 30s and 40s to 80s this time of day.
I am GUESSING that fuel/timing maps/curves maybe out of wack with air temps and going from an hour at 80mph to a cold/warm start situation...???? I guess.
I was formerly informed that the backside of the throttle blade usually gets a carbon build up.
I have had a sticky gas pedal for a few years. 1st time you step on the gas it took alot of effort then was OK. So...last weekend I pulled the throttle body and did clean a TON of build up off the inside of the bore, off the blade, and pulled what I am calling an idle by pass valve (I guess too). I had hopes that cleaning this mess would help the starting revving after the gym, but no luck...
Wondering if any help, advice, or similar situations that may be passed along.
APPRECIATE IT !!!