Idle issues when warm

[justin91lx]

So Lately my car has been running rough. Mainly after its been warmed up. When you go and shut it off and start it back up I have help it to stay running or ill stall. Takes about 10-20 sec then starts to run on its own. The idle purges a little between a 100-200 rpms. Ive replaced the iac and still the same issue. A issue ive always had was when i ran the ac when im driving. When im about to come to a stop i had to turn the ac off or the car would stall.

Today I checked for codes the only code that came up was 85 koeo, Will try in a bid to see what she spits out with the car warmed up. The smog pump has been deleted, and not sure about the canister. Any help would be great!


Okay the codes im getting when the motor is warmed up and running 21,94,44
88 mustang 5.0 5 speed manual

[Diabolic]

What's the battery voltage look like when this happens?

[TX21]

My car does the same crap. My voltage drops but the rpms are below 500 when it surges. I have a 92 5 speed with a flip chip.

[justin91lx]

Well I just recently did a 3G alternator upgrade on the car, and still does it. When i have the vacume hose off the pcv value it runs fine, but do notice a power difference