Hello, I have a 93 f150 that i recently did an engine swap from a 5.0 to a 5.8. For the rebuild on the 5.8 I put in a edelbrock performer EFI intake manifold, K&N air cleaner, and a comp cam performance camshaft. After all the initial getting it to run problems I have ran into one that has got me stumped. It now idles at roughly 1400 RPMs after it has come to normal temperature. When I start it cold it will idle at ~normal 700 RPMs. I've gone through as many threads as I could find and I've come up with this.

I have replaced these parts;
-TPS sensor
-Engine coolant temp sensor
-IAC sensor

I have also checked for these
-Vacuum leaks (eliminated all EGR components with the new engine)
-Ran with old 5.0 ECU, Same problem
-Cleaned old IAC and Throttle body
-Throttle cables in good working order

I havnt been able to pull codes yet. Lucky me, the check engine light has stopped working. Any other ideas on what could cause a high idle?
ECU compensating for camshaft?
MAP sensor?
Intake Air Temp sensor?

Thanks in advance.

 

You can pull codes with a multi meter too, lemme see if i can find the instructions...

 

quick update. Finally got around to getting a vacuum tester today. reads 18in on all lines. Also when I first start it up, no matter if its warm or cold it runs like crap for the first couple minutes and blows smoke out the exhaust. Smells rich when its doin this also. After about 2 or 3 minutes of running and a quick tap on the throttle she runs better but still around 1400 rpm.

 

oh dear... well problem solved... i realized that when i deleted all my EGR equipment I also deleted my MAP sensor vacuum tube. Great move!