Hello all,
Well I have spent some time going over many threads on this site and it is very informing but I have yet to find the answer.
As it seems to be a problem many are having I feel mine is a little different.
Just picked up this truck and it's in great shape, even the motor is new since PO changed it out with a crate motor which now has 5000 miles on it.
Now my problem is the truck runs like a champ once warm but will not idle on it's own when cold.
I removed the IAC and verified it's movement. The solenoid will not move full stroke even when I jumper it directly to the battery. Removing the connector during hot idle does not change RPM as mentioned in other threads.
Pulled the codes and only got 552 KOEO and 412 KOER. Looked around for vacuum hose problems and none found.
I tried a new IAC and the engine revs high maybe even very high and never settles down even once the engine is at temp. I have no Tach so I can't say what RPM.
Re-installed the old IAC and everything runs normal except for no cold idle condition.
Now my question, since I found nowhere a mention that I should reset the EEC after replacing the IAC I was wondering if that would have been the missing step in this procedure.
Every little bit of anti-pollution and canisters all check out since they were either replaced or reconditioned during the engine change.
TPS sensor ohms out within spec stated on Ford Fuel Injection.
I have not verified ACT or ECT as of yet. I think the ECT sensor is in front mounted on or near the thermostat but have yet to find the ACT anywhere.
I do not suspect those parts for the time being due to the fact that fast idle occurs upon changing the IAC though fast idle conditions don't go away and with the old one it runs great.
Any ideas?
Thanks!