Whenever I first crank my car, it idles very rough. It idles up and down and tries to stall. After about a minute it levels out
and seems to run fine. In fact, it runs perfect UNTIL i stop at a light or get caught in traffic. After sitting still for about a minute, the car starts to surge again. The main reason that I need this problem fixed is that I cant stay at a constant speed. When I am driving, if i let off the gas completely the car runs fine, if I give it a lot of gas its fine, but when I barely press the gas to stay at a constant speed the car jerks. It feels like the car is shifting gears whenever the rpms drop. After this happens, the only thing i can do to even hope for a comfortable drive is to pull over and disconnect my battery for about 30 seconds, then its fine again until the next traffic light. The only thing that I can think to do right now is to put the car in neutral when I stop at a light. This keeps the car from idling down and causing problems.

Any help will be appreciated

BTW, I have an 86 2.8 coupe

 

Try cleaning the throttle bore with carb cleaner. also clean the iac (idle air control) motor on the side of the bore.

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84 Z28
78,000 miles
1970 350 ci 4 bolt chevy motor punched .030 over to a 355
stock 1970 heads with 1.94's and very mild porting
edelbrock rpm cam,intake, 750 4barrel
weisco 9.6/1 pistons & rings
edelbrock headers and catback (without the cat)
700r4 trans
3.23 rear (no posi yet)