Ok, I thought I solved all of my problems that I posted earlier. I found a bad vaccum line, but still didnt solve the rough idle problem. I took it in for a new clutch, and the mechanic asked me why didnt I mention the rough idle. Well, I figured that is the best it would do with 250,000 miles on it....he figured out that one of the fuel injectors was not getting a signal to open essentially running on 5 cylinders...he said to bring it back and he could troubleshoot it further, he mentioned it could be the ecu or one of a number of sensors. Any suggestions on what it might be? I'd like to rule out a loose connection before I take it back into the shop.

 

compression test first

 

do a compression test.
the 3.slow is KNOWN for head gasket failures which do a lot of damage.

First do a compression test. If it passes, you are a lucky guy. If it doesn't, got to tear it down and find out if the HGs will be enough or if it's done more damage. Typically if they have been run with a bad HG for a long time the motor is toasted.

 

they are known for burnt exhaust valves just as much as blown h/g's

 

compression test done, found 171 on all except 1 cylinder 165; besides, that wouldnt cause the electrical signal to the injector to be zero (assuming that is correct).

 

next would be to check all your tune up items. Plugs, wires ect. Using all toyota stuff I hope

 

recently changed rotor, cap, plug wires, plugs, air filter, oil, fuel filter, battery, knock sensor, had HG done about a year ago (valves were fine then) been running fine, just popped up. Like I said, mechanic believes there is no signal to one of the fuel injectors and is causing it to run rough. I also recently replaced the vaccum lines to the ADD, had got cut open, probably by some road hazard. are there any other sensors that could cause the fuel injector to not have a signal at the connector other than the ECU? I imagine, it could be the wiring harness, maybe the injector shorted out? tried to figure out which pin on the ECU sends signals to injectors, that would be a start, dont you think?

Thanks again toytech for all your help, guess I keep coming up with more questions for you......

 

You might want to just make sure that the connection to the injector is good. The clips on the plugs break. They have to be dissconnected to do headgaskets. Since the HGs were done it's possible someone didn't zip tie the connection and it's become loose. You don't have to replace anything, just zip tie them securely.

You will have to remove the upper plenum to do this for the passenger bank.

 

I'll check it out, thanks, am just hoping, since the problem (If he isnt BSing me) is the wiring harness, not the ECU, since there is no signal at the injector. Can I get to the injectors to check the connectors without taking the plentum off?

 

Ok, I am hoping this helps someone else down the line....I figured out the new bulb I just put in for the check engine light burned out, replaced it and now I have a o2 sensor code I didnt before. The O2 sensor shorted out on the exhaust, fixed it, re soldered new wire; now fuel injector also works, guess it was shorting out. So, it looks like a lot of little things conspired against me to make the truck run bad: vacuum leaks, burned out light bulb, shorted out O2 sensor. Hopefully that nails down all of the problems.

 

If a hole isnt firing you can normally tell by looking at the plugs, to make it simple, one plug will look much different then the others.

 

I don't want to hijack the thread but I have one of those broken clips as well. Is a zip tie going to cut it?...I've heard to use a dab of rtv as well. Which is the best method? If I don't have to cut off the plug and splice on a new one then I won't .

Thanks