Idles erratically stalls & hesitates

[bravo3]

Sorry I dont know why this thread is on 4 times?? 1994 3.0 liter . no codes in ecm. complete tune up. & timing has been done. guys this is what I have done . New fuel pump and filter . New egr valve & cleaned vacuum modulator. cleaned & checked pcv valve . checked all vacuum hoses . checked cold start injector ohms ok . engine runs good cold and no skipping. thanks

[tr918]

Having the same problem with a 1993 T100 3.0L. Did you ever find out what the problem was?

[toyomoho]

Might check the MAP or MAF sensor (which every one you have), or the IAC valve (adjusts idle). Owners of other Toyota models have been spraying Seafoam into the throttle body area (inside) to clean things out. But I have no idea about this engine.

[tr918]

Thanks. Would the MAF and or the IAC cause a rich condition?

[toyomoho]

Rich at idle or hwy speeds. The IAC uses a little bypass air to stabilize idle. My guess is this amount of air is irrelevant at high RPM. The MAF controls injector timing thus controls mixture. In theory if the MAF has a problem, the ECU will go into a fixed timing mode and allow the car to be driven.

I suggest if you are going to keep this truck to pickup some kind of maintenance info. All of the components can be tested and thus need not resort to an expensive swap out method. Also the ECU should monitor these systems, have you tried to pull up any codes. AutoZone is supposed to do this for free.

Most Toyota’s have some type of mixture enrichment system when the engine is cold. Either a cold start injector or something else. Sometimes these things fail in the on position. What model engine in this truck.

[tr918]

Sorry I did not repost sooner. I had tested the IAC and MAF sensors. It ended up that the cold start injector was busted. When checked with an ohmmeter it checked fine. When the engine was running it continued to keep spitting fuel into the engine causing the rich/flooding condition.

Thanks to all,

-TR