Ok I have searched and read lots but I'm wanting opinions for my exact problem.
91 pickup 3.0
Truck blew the Head gasket, but amazing idked fine and ran good.
I yanked it out shaved heads new gaskets rings rod and main bearings. Also has brand new: ngk plus, wires, cap, rotor, timing belt, thermostat, and clutch.

Motors back in and timed to 10 with the jumper. starts up some times other times it cranks than kind of fires for a second than stalls. Other times it starts and is really rough almost like its loading up. I can stuff the gas and it gets to 2k than starts bogging back down untill it stalls.

At first I had a code 41 tps and 52 knock sensor I swapped computers the code 41 went away the code 52 stayed and a code 12. I installed a new knock sensor into the engine hoist hook. Code 52 went away but not 12. Swapped the old computer back in now I have no codes but still the same staring issue.

I have checked all my vac lines, burped the radiator. Tomorrow I'm going to swap the coil pack with another I have to see if its on the way out give a weak spark. I also plan to jumper the FP and the B+ to see if its a fuel pump issue.

Does any one have any other words of wisdom to help me out here? I have pulled and reinstalled 12 or so 3.0 motors in the past 8 months and I'm stumped on this one. Thanks in advance every one!

 

Any one?

 

Here's what it says for code 41:

• Open or short in throttle position sensor
circuit
• Throttle position sensor
• ECM

I would double-check the TPS. It manages the air/fuel mixture and can cause low idles or stalling if really out of whack. Did you happen to clean or get any kind of liquid on the TPS or throttle body? They are very sensitive.

Code 12:

• Open or short in NE, G circuit
• Distributor
• Open or short in STA circuit
• ECM

I'm not an expert on circuits... so I can't help much on this one. Make sure your distributor is installed connected correctly and measures within spec (which is sounds like you might have did when you adjusted the timing). Maybe someone else can chime in?

 

make sure the wire harness plugs are clean and fully seated, you unpluged and repluged things and stuff changed thats a good indicator that they're either not clean or not fully seated. After you've checked the sensor plugs and ECM connections, double check all the ground points are clean and firmly attached also these are all listed in the FSM wiring diagram section.

Now test the TPS signal at the ECM and verify it is registering IDL correctly, and reset/test the timing and idle

 

I just got it figured out. The wiring I did for the newer style distributer was backwards :/ swapped it around and it runs flawlessly

 

Ah good catch. Just for reference someone might of mentioned that for you if you'd of stayed in the same thread. That was you asking about the distributr swap not long ago I assume

 

Glad it was a simple fix! It seems like that happens quite rarely.

 

Yea I was sure that it wasn't the problem but I well thanks every one for all the help!