Hey guys! My 1989 Vette has started to surge. It happens when the car is in drive and stopped, and somethime in park at idle. it happens when it starts to heat up after about 160. The car is in great shape and only has 75,000 miles. I bought it from a guy who kept it in the garage and now its a daily drive so I am wondering if that has something to do with it. Any help would be great!!!!

 

My idle is gay like that because the spring and the cruise control "diaphram" i think is wat its called is worn out. Might be your problem.

 

i would check for a dirty IAC passage, vacuum leaks, and the fuel system.

 

Surging or "hunting for an idle" is usually caused by carboned throttle plates and bore. Clean the bore and the back side of the plates with carb spray and a brush by having someone step on the throttle and holding it wide open while you spray and clean. Then reinstall MAF duct. Then disconnect your battery for about a minute so the computer can relearn idle posistion. Start car and go drive it for 3 or 4 miles in stop and go to relearn. [8D]

 

Thans guy, I just have two questions, one: what is the IAC passage? and two: what is the MAF duct? In response to mech259, are you talking about cleaning the inside of the trottle body? Or the opening?

 

Inside the throttle body, where the throttle plates meet the bore. Don't think you have to worry about Idle Air Control passage. MAF duct is the plastic that goes between the throttle body and air filter. [sm=signs003.gif]