I have been having a random stutter since about a month after I did my top half rebuild. I figured it was an ignition problem and so I have tried replacing my plugs, wires, cap, and rotor twice each. I have taken the truck to a Toyota certified master technician, and he didn't find the problem either. All he said was to try OEM plugs, wires, cap, and rotor. I have checked the gap at the distributor and tried playing around with more or less gap on that. No help there. The coil tests out okay. Fuel pump was tested by the Toyota tech and he said it was within spec for pressure, though on the weak side of acceptable. I am hoping it isn't an injector going bad, but I was thinking maybe one of them is not always firing. Other than pulling them and sending them in for service, I don't know how to test injectors.

I am at my current frustration limit on this project.
Anyone have any ideas on what could be causing this issue?

Edit: Oh yeah, 1986 4Runner 22rec.

Your problem sounds like a corroded connection to your injectors. Can you wiggle the wire harness about 10 to 12 inches up from where the exposed injector wires come out, and make the engine stumble, or run better? It seems to become more of an issue with age on these 22RE set-ups. Peeling away 10 inches or so of the insulation from the injector connections will expose how the wires to the injectors are spliced in.

Thank you very much.
I will check this as soon as I get a chance.

A quote from a thread and words from Esquire812....

I cut the harness open and found the butt connectors, but they don't have any corrosion. I can also bend them and tug them in every direction without any change in performance.

Man, I was hoping it would be something as simple as that. I think that I will solder those wires while I have it apart, just in case. Thank you very much for the input Staceman, I now know to watch for that one in the future.

I also noticed now that it will idle nice and smooth until I bring the revs up, then it stutters at higher revs and once I let off the gas it idles like crap. I'm thinking that I need to meter my TPS, but that will have to wait until tomorrow.

Any other ideas?

Start with the TPS. Did you clean the EGR and the t'body while you had things torn down?

There's a flow test for the fuel injectors in the FSM; that '93 FSM we have posted here will suit your needs. If you happen to opt to send them off to be reconditioned, send the CS injector along too.

www.rceng.com or
www.witchhunter.com

Years ago my 86 4Runner had intermitant injector cut out...
In the end my "phantom problem" turned out be a leak in the windshield on the passenger side right over the ECU.
Moisture would do strange things to a perfectly tuned motor and I plulled my hair out for over a year trying to troubleshoot.
I finaly replaced the ECU when I drove into very deep water/mud hole, flooed the cab and fried the ECU.
Now the ECU sits higher behind the glove box wraped in plastic and sealed with RTV and zipties.

Good luck and keep us posted...

Holy. Crap. That sounds like a nightmare.

I have started checking each thing one by one.

The TPS is reading good on all but the .85 mm test where it is still getting continuity. I know that this was good when I put back in the throttle body in December. It was way off wack before I messed with it in December, and I thought I could get away with just cleaning and adjusting it. Since my marks tell me it hasn't moved, I think that I should probably replace it. Could this actually be the cause of all my headaches?

ECU is definitely dry, I have had the truck parked in the garage for a long time now.

I cleaned the throttle body and EGR when I had everything torn apart. The plate that mounts on the back of head and has the pipe in it that runs from the exhaust to the EGR was totally crapped up. So I spent some time cleaning that out. The haynes manual says to pull the vacuum line at the EGR and connect it to vacuum to test the EGR. So, I did that and the engine immediately dies. This is what's supposed to happen right? So, I think that the EGR is good.

On the injectors I am going to need a hook pick to get them unplugged in order to meter them. So, I will bring one home from work and check those tomorrow night. I will also try to listen to them to make sure they all sound the same. I just really don't want to have to pull apart the intake manifold, but I guess to really give the injectors a proper test I will have to.

Is there a reasonable way to replace the TPS without pulling the throttle body? I figure I want to replace the TPS before I start pulling injectors, in order to see if that fixes it. However, I don't really want to replace the gasket on the throttle body, and then if that doesn't fix it, have to pull the intake manifold and replace that same gasket again in the process. So anybody know a trick that isn't too difficult?

Almost forgot to ask. Could this problem be related to the PCV? I had to replace that on my 86 pickup a few years back and I remember it running like crap from the emissions center, where the guy broke it, until I got the new part. The pickup has the carburetor though, and I don't know if it is the same on the fuel injected models. The one on the pickup is plastic and comes right out if you pull on it, but the one on the runner is a metal piece and it does not seem to want to come out at all.