Hello again, Yotatech:

My 88 4runner 3.0 AT has been acting out and I am at my wits end. It started a while ago with being hard to start when it has been warmed up. Particularly after a drive and sitting for 20 minutes or so. Other than that on its first initial start of the day it runs great. But after sitting it cranks just fine. It will fire but not catch. Over time it has gotten worse. I was on a deep forest trail about a month ago and in any situation I would have to tap the gas it would stall as soon as i let off. Now i cant get it to start at all without ether. When it is running it runs rough. It surges right above idle and will stall when you let off in gear. Symptoms point to a vacuum leak but i have found no such thing.

Things I've done:
Tested Fuel Pump in every way possible without a pressure guage.
Jumped the terminals at Diagnostic(pump turns in a sends fuel)
Reads 12v at fuel pump.
.9 ohms through pump.
Relay clicks on as it should.
Replaced the Fuel Pressure Regulator with one from a parts motor.
When I jump the FP terminal I can hear fuel passing down the return line
Swapped the VAFM
It will idle up if I manually advance the VAFM.
Replaced the ECT
Replaced the TPS. It is perfectly dialed in
Adjusted the timing to 13 BTDC
Replaced Fuel Filter
Tested for spark
Checked for cracks in the Intake Boot
IAC doesnt seem to be closing all the way but covering the port doesnt seem to improve anything.
Replaced EGR.
Ran an unlit Propane torch all over the engine bay
Pulled the PCV hose and covered port

On my last session I threw my hands up (@$%#*&!) when i blew the EFI fuse (15amp) for the second time. I'm thinking i will pull the Plenum off to check the gaskets but i dont expect to find anything. I cant think of any other reason it would not run right. We have Fuel, Spark, and Compression. Any input???

 

Bump...

 

Air filter? Interesting that it idles up by moving the VAFM.

 

Air filter is so so. It's the same without the filter. I rented a fuel pressure gauge and the fuel pump checks out. I'm going to pull the plenum and check the injectors.

 

I don't know what type of tube goes from the VAFM to the throttle body, but on the 22re they will crack and break and cause problems.

 

I dont know the 3.0 but the fuel systems do get dirty in these trucks. Fuel rail gets gunk in it, and you could have some crud in your injectors screens that could keep fuel from flowing.

A contraption I have used to test injectors is a syringe with injector cleaner in it, with a hose attached, to the injector and using a 9 volt battery for a second at a time to operate the injector to clean the injector. You can attach the hose at both ends to flush and reverse flush the injector.

I got it posted in one of my build threads somewhere but dont remember which one. I found it on you tube on flushing injectors.

 

Well I just pulled all of the injectors. They're weren't to bad. I pressurized and activated them and each sprayed pretty well. I pulled the plugs but they don't seem too bad. I will buy new ones as well as wires, rotor and cap.

I have checked the intake tube about 100 times for cracks. I've checked for vacuum leak at every possible point. The fuel system checks out so that an leave only the ignition system.

 

I have the exact same symptoms you described, in a 96 tacoma with 2rz 4cylinder. Did you ever discover what was wrong and a repair to solve this problem?

 

Of all the things wafoogalla tried, he never mentioned looking at the Fuel Pressure-up system. His symptoms sound like vapor-lock, and that's what the Fuel Pressure-up system addresses.

I don't know anything about Tacomas (this is NOT the forum for them), so you might get out your manual and see what your truck does about vapor lock.