QUESTION for GotEngines.com: I have a 1991 Toyota truck 4×4, manual shift with a 22Re engine. I recently replaced the air flow meter and now the rpm’s surge up and down when the clutch is pressed in or in neutral with the brake on. when I let of off the brake, the idle smoothes out. The engine light does not come on. I talked to a mechanic who checked out the truck for the previous owner and he said that he checked the vacuum lines and adjusted the valves. I also can’t adjust the idle. It is adjusted all the way clockwise and when I try to adjust it, the rpm starts to surge without the brake on. It idles about 1800 rpm most of the time. Before I bought the used air mass meter, A friend let me try his from his Toyota truck and it did the same thing. Any help you could give me would greatly appreciated.
Possible problems: It’s is possible that you have several problems. First off, just to be safe, check the connection on your TPS (throttle position sensor). It could be loose, corroded or slightly disconnected. Have your throttle sensor tested as well. The throttle sensor is what advances your timing and controls your injection pulse width during idle and acceleration. You might want to consider obtaining a wiring diagram from you local library and trace the brake wiring circuit to look for faulty a short.
My suggestion to start with after you give it a visual exam is simple and straight forward. Have the truck examined by a competent engine specialist. You are getting into a big puzzle regarding the entire computerized system. It is imperative to go through a diagnostic procedure. Realistically speaking, only a qualified mechanic with a high technology scan tool, who knows how to use the tool can find the problem.
Most cars are using the computer to control idle speed, there is no more ‘idle adjustment screw’ on the great majority of vehicles built from the early ’90s have computer controlled systems. Without a person who can use the various functions of a scanner, you are basically climbing a greased tree. The scan tool will check the parameters of every control assembly on your truck. Sometimes one small glitch (which does not put the engine light on) can seem like a big deal because it makes the vehicle run poorly.
The point is that asking people on a forum, who may not have any more knowledge about cars than you is a sure way to spend a lot of unnecessary money on replacing parts, as opposed to diagnosing the problem right off the bat and fixing it.
I see problems of this type that turn into major failures, even damaging engines so much they need to exchanged for a rebuilt engine. The odds of this turning into a rebuilt engine are slim, get it checked out anyway, it will cost less than waiting. If you need a good used engine control unit for sale we stock them now. We also have a tremendous inventory of good used low mileage engines for sale and our upgraded remanufactured Toyota truck engines for sale. For any further info and a free quote call GotEngines.com @ 1-877-268-0664.
FYI: When a standard transmission jumps out of gear, it usually means that the clutch was not aligned properly during installation.
Great one. I read your Possible problems and it is really informative.
Does anyone else think that with the growing intricacy of cars and technology, that there is no longer a car mechanic but instead a car technician?
I have a 1994 Toyota 4X4 with a 22RE engine and I have a similar problem. When I stop with the AC running, my truck almost turns off and the RPM’s go up and down. It runs fine on the highway and it does this same thing when the heater or defroster is running. Does anyone have any sggestions?