Hookdbyvettes

Hi All, first it's a '86 vette, no power add ons (empty cats), new plugs, wires, cap & rotor, OK fuel pressure. Drove it yesterday with no problems as usual. Started this morning and went to the store with no issues, but upon returning the engine kicked back while starting. Idling was fine, but as soon as I began backing out I noticed a miss or stumble and pulling forward, driving through the parking it was stumbling or misfiring. Once on the main drive, just getting up to 35mph was a chore & embarrassing, however the cruise was ok the check engine light was on, I haven't had the time yet to check codes. I don't have much turn around time, so I can't give codes yet. (Going to the doctor's office in a few hours.) The rest of the trip home was rough on every acceleration until I hit the speed I was to cruise at, then smooth running, though cruise below 1700RPM was a little rough, seemed it had odd misses. I didn't mention this first, but as the RPMs got higher, the engine ran & accelerated smoother. The problem began smoothing at around 2200 RPMs and almost seemed to be gone around 2500-2700 RPMs. I dealt with the problem for about 7 miles, going up & down long hills. As I turned into the tangle of neighborhoods (4 mi. to home) The engine smoothed out accelerating & the check engine light went off. I decided to pull into my mechanics garage area (1.5mi. from home), shut down & explained the problems. After listening carefully, he stated the kickback upon starting & poor performance at low RPM starts & stops, as well as accelerating to the speed limit (max 45mph), but good higher RPM performance, indicated to him that it could be the internal mechanical advance of the distributor if the '86's had them. He advised before bringing it to him check to find out if it still has a mechanical advance & make sure it's not sticking & freely moving, as well as checking codes, also checking the internet for similar problems. Upon starting, He & I listened for the kickback, but it did not occur, nor did the acceleration misfiring on the last 1.5 mile trip home. The idea my mechanic guessed at was the only idea I had myself. So any advise & information will be greatly appreciated. Going to see the Doc, Thanks again.

383vett

The distributor does not have a mechanical advance. It's all computer controlled. Check for stored codes. Before doing anything.

Cliff Harris

Pull the codes with a paperclip:

http://corvettephotographs.com/c4vettes/codes.htm
https://www.corvetteforum.com/forums...post1574918379

Then go here to find out what they mean:

https://www.corvetteforum.com/forums...post1576116036

Hookdbyvettes

I haven't looked up the codes, I've been out on sick leave for almost a month, but in all my trips to the doctor, I've had no other issues so far, if it happens again, I'll go straight to the codes.

hcbph

I had an issue a while back, not the exact same as yours but some symptoms are so I'll pass it along.

Start, idles and drove fine till the temp got to be around 165 degrees, then barely ran and always happened a few blocks from home. Shut it off and wait 10-20 minutes and restarted and ran fine for the rest of the day. Almost always did it when it was cool outside and first start of the day. There was an error code (36 or 42 maybe) that indicated a problem talking to the ecm. Chased my tail on that one a while checking and cleaning grounds, connectors etc. with no luck (mainly because after sitting a short time it ran fine and that didn't seem logical if it was the ecm). I kept coming back to the IAC even though the codes didn't indicate that. One day it happened and I happened to have a plastic faced hammer with me, I gave the IAC a couple a light taps with it and the problem went away.

I'm guessing the IAC was sticking at times and that freed it up. Has not come back and planning on replacing the IAC this winter if everything goes as I hope.

Good luck finding your issue.