90 Tracker idles, dies above idle

[GeoCacher90]

Hello again,

After several months with no real problems, the Tracker has an issue. It's a 4wd LSI with MT.

Last week leaving work, engine still fairly cold, I noticed it would bog down when I hit the gas. It was annoying, but never died. Cleared up after a minute once it warmed up.

Then the other day... Not good. I was going to drive it to work. Started, idled fine, but then when I hit the gas, it wanted to die. Barely touching the pedal made it want to die. Letting off quickly, it would recover. Push the gas for to long ( 1 second or more) and it's dead.

I looked at it today (good weather). It idles fine, and this problem happens with engine cold or hot. If I barely rotate the throttle shaft, it will cut out and want to die. If I move the shaft extremely slow, idle increases a bit, then it cuts out.

I tested TPS with ohm meter. Idle switch works. Idle TPS is at 1.5ish kOhms, and at WOT it's around 5kOhms. It appears smooth, no glitches.

No CEL, no DTC's except "12."

Has anyone experienced such a thing before? It's extremely frustrating because I thought it would be the TPS for sure.

Thanks!
Wes

[fixkick]

all 90s do that, its super old now.
never seen any 90s run right , until fixed.
first off the 90s ECu does fuel only so if spark bad, it will misfire or stall.
to cause on all old cars is not doing a full tuneup. #1 for 100 years now.
older the car the more true.
if sparks ok,
then sounds like low fuel pressure, or the map hose is clogged with gunk
is the CEL glowing driving?
its not the TPS, because the TPS can not effect WIDE OPEN THROTTLE PERFORMANCE, ever. THE MAP does that. the MAP and ECU brain calculated air flow then does fuel tables to set fuel injection rates
its not the O2 sensor either its off line accelerated in any way possible.

that is correct 99% of all posts of all forums love to blame TPS for everything and are DEAD wrong
it an old race car with custom ECU that is called ALPHA mode, that only runs engine off one sensor TPS, not in the least like that system long gone and track race only.
the TPS bad causes only tip in power losses and never WOT. the power hesitates then CATCHES UP TO FULL POWER< is NOT TPS caused .

the #1 reason is low fuel pressure.
causes are:
fuel filter clogged, (tuneups do work)
FPR stuck wide open , pressure at 10 psi not 30.
Pump weak or not getting 12vdc to the pump , on 2doors, super common low volts there, you never told door count so......?????


here is key symptoms
If I move the shaft extremely slow, idle increases a bit, then it cuts out.
and if WOT power is gone , its not TPS.
for sure.

do pump pressure next if spark plugs are not 20 years old.