I figured, why not, I’ll tackle it. So I went outside, pulled the throttle body apart, took the IAC motor off, and – lo and behold – it’s got a pretty good amount of carbon and shit caked on. I also noticed that the air filter was filthy, and the housing had a fair amount of leaves in it – she’d also been having an issue with throttle responsiveness, so I figured that might be the cause for THAT problem. So I went to Wal Mart to get some throttle body cleaner and a replacement air filter, came back, cleaned out the IAC motor, and dropped in the new air filter.
While I was at it I took a look at the inside of the throttle body, and this is the part that really floored me. It was clean. Like, brand new clean. I sprayed a bit of the cleaner on and around the throttle plate and wiped it off, and the rag came back damn near perfectly clean. There was also not a drop of oil to be seen anywhere in the intake or throttle body. This says to me that this motor has zero, or as close as you can reasonably get to zero, blowby – which, after 130k miles of my mother’s driving, says to me that Ford makes one damn high quality product.
So anyway, I put everything back together, reset the ECU’s idle parameters, and then we went for a ride. The idle issue was completely solved, and even I, from the passenger seat, could feel the difference in throttle response and power. Previously it had some hesitation, which it certainly does not anymore. It also shifts smoother, both down and up – I guess the restricted airflow was actually causing the motor to not meet the transmission’s power delivery expectations. The transmission still needs a fluid flush, but it’s certainly a big improvement.
So, the moral of the story is, Ford quality gets a thumbs-up from me.