My 93 PU is finally acting up (195k). It stumbles on light acceleration. Idle is usually good. High speed is good. I am working my way through checking the easy stuff, but I expect my attention will eventually turn to the injectors. Have run a bottle of Techron and a bottle of Progard through the thing, no improvement.
Other than a pressure test (for leakage) and resistance tests, is there any way to assess the performance of the injectors while they are installed in the car (it isn't that I'm too lazy to pull them, it is just really, really inconvenient)?
Are there any other obvious culprits for this kind of behavior? Does this sound like injectors?
Have you replaced the fuel filter? On the 22re (as well as any fuel injected engine I imagine) if the fuel filter starts getting plugged the pressure to the injectors won't be consistent. I've found on my and my wife's 22re's that I know it is time to replace the fuel filter once I start feeling sort of a "chugging" feeling at lower speeds and rpms.
Already cleaned the thottle bore and readjusted the stop (throttle had been sticking closed), but that didn't help with stumbling. Was putting off the filter 'cause other cars (long ago) behaved differently when filter was clogged, but if it works for other people, I'll do it.
Not sure why you are targeting the injectors. I suppose they get diry if one buys crappy gas, but my understanding is they don't actually 'go bad' that frequently. I recently pulled mine at 295,000 miles and they looked great. I tested them and found no leaks and the spray patterns looked good. I changed all the o-rings and stuck them back in, fully expecting to get another 300K out of the little bastards. They have never been 'cleaned,' yet the ports were clear and the micro-mesh screens inside them looked brand new. Of course, all I have ever run is Amoco 'white' gas. Don't know if that has anything to do with it, but it can't have hurt.
I don't think there is any good way to test the injector in the car. The Toyota delarship tells me that they have a machine that hooks up to the enire fuel rail and they use this to test them as well as to flush them. But, my understanding is that is off the vehicle.
If you have eliminated vacuum leaks, what you describe sounds like a possible ignition problem. Have you ever changed your plug-wires? You can check the resitance (25 kohm max) to see if they are actually 'bad.' However, if they have not been changed, they are certainly overdue. Obviously, I am assuming that you have eliminated the plugs as a problem and checked your timing. It could also possibly be a coil going bad. That's checked easily enough with a multimeter as well.
Once ignition is eliminated, gas pressure would be a good thing to check next. If you have good pressure (38-44 psig), you have immediately eliminated the fuel pump, filter, and pressure regulator as a source of problem.
After that, it may be time to take a hard look at the injectors.
yeah, i would have said throttle-body cleaning or fuel filter clogged also..... my 95 acted that way with both.... Also, you might check the vaccum hoses coming off the Throttle -body and do a vacuum test on the EGR valve.... easy to do. conceiveably could be the O2 sensor(s)...
Thanks. I think I have found the immediate culprit: the EGR valve. It allows gas to pass when closed (I suspect it should close completely, but I have not been able to get a definitive answer on that). I have blanked it off and the engine runs quite nicely now. Of course I could remove the barrier and find the engine still runs well, with my luck. I plan to remove the EGR valve and see if I can clean it (I am not sure how well that will work, since there does not appear to be line-of-sight access to the valve area from either port). The engine does not knock when blanked off, so I suppose I could run that way until I go for an emissions test.
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