I thought I'd be able to fix the problem myself, but this is the last kink I
have to overcome to have a 100% working engine. I searched the archives but
can't find any problems EXACTLY like this, so here goes.
Truck runs perfect under ALL circumstances. No stumbling, no strange
idling, no stalling, no engine codes. Everything is kosher until I push the
pedal to the floor. Truck goes like stink, but when I let off the throttle,
the idle hovers around 2.2K pretty much permanently. You can rev the engine,
continue to drive, switch the tranny into another gear, but it will continue
to idle at that speed. It's very annoying to sit at a light and have the idle
revving at 1300 rpm with the truck in gear! Now sometimes if you give it a
good 1 second wail on the throttle and then let go, the idle will come back
down to normal (it won't work with anything less than WOT though). Now if I
shut the truck off and restart it, it will return back to normal, with no
engine codes. Now this is what I've tried so far:
I've replaced the IAS, TPS, and the MAP sensor, to no avail. I took off
the throttle body, and completely cleaned the unit, making sure the MAP
vacuum port wasn't clogged. I also cleaned the IAS plunger and port. I
checked the wiring, and verified that the throttle cable isn't sticking. I
tried adjusting the throttle blade angle, and that didn't work. It does this
with or without the supercharger, and I've even tried swapping ECUs....all to
no avail.
I can't think of anything else. The only thing it could be is the
throttle body itself. I find that hard to believe though, after all the TB's
just a hunk of metal with really no movable parts to fail other than the
throttle blades, and those have no play in them. The only spare TB I got is
the V6's, and I've thought about throwing it in temporarily to see what
happens, but with smaller bores it will increase the vacuum, which defeats
the purpose of a direct swap. I've checked for vacuum leaks, which I can't
find. Even when I had a vacuum leak in the past, it never acted like this.
So, what the hell else can it be?!?
-Austin
Vipertruck
This archive was generated by hypermail 2b29 : Fri Jun 20 2003 - 11:57:30 EDT