95 F150 needs help
I have a somewhat unusual problem. I have a 95 F-150, 5.0 Lt., auto trans. When starting the motor the check engine light flashes 4 times and the idle speeds up momentarily, it will then drop and sometimes nearly stall. The idle is erratic for 30 seconds or so and smooths out and runs fine. This happens at cold start mostly but has happened when warm as well. This past weekend I replaced the throttle body with Ford parts for an unrelated problem. The new throttle body came with a new IAC and TPS, again both new Ford parts. Cleaned EGR and replaced PVC. This has made no change. I am unable to retrieve any codes other that the “system pass “ code. Other than this the engine is running fine, no burning oil, no change in fuel mileage, has good pickup, and no apparent vacuum leaks. I am writing to you today to see if you have any suggestions as to what I may be overlooking or if any of you have had similar experiences. I would like to thank you in advance for any help you may be able to provide.