Engine Lean at startup that goes away after a couple mins or 1 to 2 revs


New Member
May 17, 2019
So I've had an issue on startup that I believe is affecting driving some as well that I have been trying to fix for months with no luck. Its a 91 with heads, intake, cam, etc and a tune. I ended up having a vacuum leak that I was tracking down for awhile and finally got that fixed but the problem still persists and is better but still not right.

The issue is every time the car is started up, it runs lean and idles lower than it should for a varying amount of time depending on how hot or cold the engine. If its cold it may take a few minutes but if its hot it may only take 20 seconds if that. You can also expedite the process by revving it a few times to about 2k and then it will hang around 1200 rpms then drop to the correct idle and the A/F ratio is fine.

There is no codes being thrown to go off of and not very much info online with others having this issue I saw only one post really (posted below) where someone else had this issue but there really wasn't a solution found to that one. If anyone has any ideas or advice it would be greatly appreciated

  • Sponsors(?)