Ok I think I FINALLY have this all figured out.

IF YOUR TRUCK IS IDLING VERY HIGH 1300-2000RPM TURN IT OFF. Read Why Below.

First of all: DO NOT, JUST reset the ECU. Because there is a REASON your vehicle got that way in the first place. You will just be back paying a shop 1hr worth of time to reset it again. FIX THE PROBLEM.

In my case I believe it was the TPS [Throttle Position Sensor]

I had a high idle, my TPS AND IACV [IDLE AIR CONTROL VALVE] [STEPPER MOTOR] SEEMED FINE. But it was only because my ecu went into limp mode.

Here is a simple way to check them,

IACV With your truck running, the Idle point should stay the same with the a/c on or off. It might jump or fall for a second because its delayed but it adjusts back. If your IAC is BAD it will fall when a/c is turned on and stay there.

TPS Heres where I messed up the first time. I figured that if I simply unplugged the TPS or removed it while it was plugged in and made sure it was at 0% or closed position the engine would idle at 700 where it should. But it doesn't if its too late. If your truck goes into limp mode its going to idle high no matter what the TPS reads. This is so that you can drive. If you pull a TPS off of the throttle body while it is plugged in and drive to drive it will buck, stutter, the ecu raises the RPMS so that you can still drive it without these issues.

I would have never knew this if I didn't have a scan gauge. At first I could see that my TPS setting was wrong, it was 21 at idle and when I pulled it off it went down to position 6 which would allow the engine to idle at 700RPM. However after a while the ECU noticed it was not getting correct readings from the TPS and went into permanent limp mode.

IF YOUR TRUCK IS IDLING VERY HIGH 1300-2000RPM TURN IT OFF. Run it as little as you can. I probably started mine about 8 times and ran drove it about 4 times before it went into permanent limp mode. NOW it needs to be reset and i believe the issue was just the TPS.

I have a new ECU [16$ at junk yard] and plugged it in and my it ran correct. [My TPS is still jumping, but when it was at 11 it idles perfect] I instantly shut it off and am now waiting for my new TPS to come in.

 

See, this is the kind of crap we need members doing, if you have a problem and you figure it out tell us.
If someone else comes on here and does a search and they find this this could save them a ton of time and $$$.
Not to mention I read almost every single post and I file useless crap like this in the back of my skull for later use. (I cant tell you my phone number but I can tell you the size wrench you need for the fan clutch on a DI)

 

Maybe we should make a stickies section.

A Sticky for common issues/fixes or something along that line and just post the links.

 

I am working on it, a DI sticky only section.

 

Heres a symptom of a external head gasket leak I never heard anyone mention. Your lower windshield will constantly fog up with dense condensation at night or late evening.

 

That is with a leaking heater core.
As the coolant evaporates it will condense on the inside of the windshield.
If you wipe it with your finger and then taste it will be sweet if it is a old batch of coolant, really bitter if it is a newer batch.
They now add a bittering agent to coolant to keep kids and animals from drinking it and dying a horrible slow death from kidney and liver failure.

 

Im sorry I thought I typed EXTERNAL windsheild.

Its the external part that fogs up with HEAVY condesation. My heatercore is bypassed anyway.

 

Screw you for living in a nice warm place! LOL

 

lol i hate it here and will gladly trade places with you!!

We have two seasons hell and freezing.

Thank god im going to college this year! I don't have to work outside in it everyday!!!!

Im just delaying the heatercore fix, just hoping its the oring deal-io i have heard about.

 

Two questions, if the tps was sending a bad signal enough to go into limp mode wouldn't it show a tps code? And does this apply to obd1 discos(94-95).