toomster

Hello all here's the new situation. I now have the 1990 4 door 22re 4runner up and running. But I have an idle issue that I cannot for the life of me figure out. It is supposed to be at about 700 RPM. I have set the engine while good and warm to 700, and the engine keeps on dropping down to 200 - 300rpm. I have tried adjusting the air bypass screw as well as the Allen head bolt to adjust where the throttle plate sits. Both have not stopped it from "automatically"adjusting the idle down to 200-300rpms. Also while this is going on I don't know if it is a cause or an effect of it, but I am getting the error codes for rich and lean at the same time. I want to check the O2 sensor but aside from some one stating that I need to make sure it hits 1 volt 10 times in a min. Is there anything else I should be checking. Thanks all.

abecedarian

When you adjust the idle, are you also adjusting the timing?

Lumpy

Start by cleaning everything...clean out the TB, check plugs, cap, rotor, be sure the AFM is not sticking and moves freely. As Abe stated check timing as well. When mine started this the knock sensor went and it did toss a code. Something else to think about.

abecedarian

Forgot to mention that the ECU uses throttle position, engine RPM, coolant temp and air-flow to calculate timing. Ignition timing affects engine RPM and air flow, and to an extent coolant temp... etc. TPS is about the only thing not changed by temp, timing or air flow changes.
Another thing, if the coolant isn't coming up to temp properly, the idle air valve / auxilary air valve under the throttle body may not be operating properly- holding slightly open until it's warmed up causing the idle to be higher until later. This could be clogged water passages causing this or could be the thermostat holding the coolant temp low until enough engine heat is conducted from the head through the intake to the throttle body.

toomster

Prior to this happening, I had a TPS out of adjustment. I adjusted it, and in the process tried to clean the TB as best as I could. I found out about the TPS though because I couldn't get the idle set. I will certainly check, but I think the timing should be on. That was only one or two months ago I set it. I have a can of seafoam at home. I'll try to run some of that through the ole beast this afternoon to see if that does me any good. Also am I correct in thinking the O2 sensor needs to hit 1 volt 10 times in a min? Thanks all, I sincerely appreciate the help.

toomster

Hello all,
so here is the result. I ran some sea foam through the system, and found a small leak on the Exhaust injection system. I did check the timing and that seemed dead on. I also checked the O2 sensor, and at idle it stayed right at .7 volts. It did not fluctuate. I'll try to tighten the injection system tonight. Thanks all.

toomster

Hello all,
so I still ahve the same problem. I tightened up the air injection system, and I still have the same error code showing on the engine. Any one have any ideas what to start trouble shooting now?

Thank you