[Gmecm] Tracker TBI problem solved!

[Cowen]

Hello folks!  First let me thank all of you for your
suggestions re: my wife's 1992 Tracker.  To recap, it
was getting poor mileage, failing emissions testing
because CO was spiking off the scale every time the
throttle was increased, and hesitating on
acceleration.

When I asked you guys for advice, I had already
swapped in known good O2, TPS, MAP, cap/wire/rotor,
ECM, plugs.  I had set the valves, confirmed the
timing, cleaned the EGR (which was completely
plugged)and PCV valves, inspected the injector for
spray pattern and leaks, and confirmed the purge
canister worked.

Following your suggestions, I confirmed the fuel
return line to the tank was clear and confirmed the
MAP port on the throttle body was clear.

All of this made no difference.  I finally decided to
do some investigative surgery, so I pulled off the
Thottle Body... and found the gasket to the intake
manifold was disintegrating!  The gasket was coming
apart like wet paper, and the soft chunks were moving
through the throttle body, plugging ports, although
there were no external vacuum leaks.

After installing a new gasket for a whopping $3.28, it
runs perfectly.  I haven't had a chance to emissions
test it, but the difference in driveability is night
and day!

I've never seen a failure of a gasket like that, where
it just started rotting away on an otherwise excellent
engine.  As far as I can tell it was OEM.  Funny
though, I fell into the trap of thinking that if the
car ran poorly, it was likely a failure of some
complex component.  Thinking back with 20/20
hindsight, in my limited GM, Suzuki, and Toyota EFI
experience, I haven't seen a "failure" yet that wasn't
actually a broken hose, gasket, or wire!

Thanks for the advice folks, thought you'd like to
know how it worked out.  

Duncan 

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