Full Lean in Closed Loop Operation?

[Kingtal0n]

Originally Posted by WithHonor037

No its manual. I mean when the clutch is pushed in between shifts the rpm would jump. The engine was rebuilt a year ago so its by no means fresh. it runs too smooth when cold to be a compression issue.

I went back to basics first and have the manifold torn apart. Ive had a lot of vacuum leaks in the past so im doing my best to absolutely eliminate it as a possibility.

I checked all my grounds and couldn't find anything loose. I didn't go as far as to check resistance through wires yet.

Just boost leak check the engine for potential air leaks, dont bother pulling it apart. If there is a leak after the maf, unplugging the maf would help it run better, and the idle would be higher in both situations (maf / no maf).
did you try the ecu reset / unplugged O2 sensor yet? those order of operations are diagnostics to make conclusions.

Its usually the simplest thing. Do you have an air filter on the maf? try to upload a picture of the engine.

A vacuum leak makes sense but it would need to be very large. When cold the enrichment provided allows the engine to run normally, but the idle would have to be very high. Once warm the air leaks cause a lean condition, but the O2 would compensate and the idle would shoot up. however, there is a max compensation, but it is still enough to cause a very high idle. the rpm shooting up 2,000 between shifts indicates a vacuum leak of course. engine speed is controlled by air, not fuel, for the most part.