ive swapped a 95 mustang H.O. 5.0 into my 1990 f-150 in place of the original 5.0 due to a cracked head. the engine runs perfectly but i am now noticing a slight surge in the idle when the motor is alloed to idle for more than a minute of two. at first i suspected the TPS (it didnt do this with the other motor), but could this be due to the lift and duration differences in the original cam and the gt cam since the truck is speed density? my experience with mustangs thru the years has tought me in a density vehicle even a slight cam change will cause this same issue. i guess it might be time to convert it to mass air.

 

Did you use the 95's ECU? The 95' wasn't MAF?

 

i still have the stock 90 F-150 ECU. im probably gonna go to pull-a-part next saturday and get the mass air conversion stuff.

 

The 95' was MAF, but it didn't come w/ the engine?

 

The PCV is functional & airtight in the mount grommet. The air intake was not removed. No Vac leaks? Cleaned & tested the IAC. Ran error code scans.

 

correct.

yeah everything checks out, not a big deal, other than idle it runs great.