Scottm 2010-04-18 12:25:44
take a trip down to pep-boys or the like and take a look at their books. I
bet it will have at least some EEC 4 stuff.
Do you get any codes? Do the key on engine off first—-fix codes. Then do
the key on engine running—fix those. Lower code numbers first.
Does your scanner tell you to cycle brake pedal, cycle AC, Go wide open
throttle(WOT) turn steering wheel one full turn? ANY of that stuff during
the key on engine running test? If not something is wrong…..Its been a
while but I think alot of the voltages, resistances, ect are the same on
those same years. If you have NO codes, It sure sounds like the IAC is
sticking. I would take it back and get another one. Tell them it worked for
a week then went goofy. It would not be the first time a new part was bad.
Or shoot some wd40 in it and see if it changes anything. Check ecm
connections under the hood, at least unplug, look for corrosion, and plug
back in.Look very closly at the ones near the battery(acid), be sure the do
the main harness at the ECM too. Someone mentioned the egr sticking but
that will usually set a code and give you the CEL (chk eng light). If you
had the emmisions book you could go to the rough idle part and have fun.
Take a look at those cheap chiltons books or ALLDATA online, or a manual on
DVD maybe? I have never used alldata online. I know the cd version is
good(look like the ford book scanned) Search the net for FORD EECIV too.
The TPS should be about .6 at idle and slowly go up to about 4.5v as you
open the throttle all the way. one off the wires going to it should be a 5
volt reference .