[basspaul]

My wife's 2000 4Runner will intermittenly not accelerate at all. 3.4 V6 5VZFE, auot trans 4X4 181,000 miles. No trouble codes. Sometimes will pop from exhaust. Feels like it is not getting any fuel at all. Stop vehicle, turn ignition off and back on again, runs OK. Have cleaned MAF sensor wires. Is this a bad tps? Thanks for any and all help in advance.

[TxGreaseMonkey]

I suspect the problem is with the Ignition Control Module (ICM). Easy to replace.

I would not run the vehicle, until you replace the ICM. There's risk you could blow the exhaust system off, when excess fuel builds-up and is then intermittently detonated. I recommend replacing ICMs every 120,000 miles or 10 years, whichever comes first. These are problematic components. Be sure to apply heat transfer compound to the back of the ICM; otherwise, it may not last long.

Conceptually, the ICM is a large output transistor (switch) controlling current through the primary coil. ICMs replace points and condenser in older vehicles. In the primary coil, current builds to 5 to 12 amps, generating lots of heat (due to inductance). Then, the ECM controls when the ICM "switches off" current to the primary coil, causing amperage to go to zero. When this happens, 12 to 14 volts in the primary coil is "stepped-up" to 30,000 volts in the secondary coil. This process creates a "type" of alternating current required for the coil (step-up transformer) to work. In a properly working ICM, timing is precisely when needed to fire each spark plug.

[kitch428]

Try disconnecting the battery and let sit 5min. Then let it relearn parameters. Drive the dog snot out of it after warm up.
Let it cold soak, then drive it through full warm up normally.
If it continues, I imagine the original hot wire in your MAF is just plain worn out. Get a new one anyway.
Fuel injectors should be flushed through a pressurized system cleaner on these 3.4's every 30k. Seems like the only ones that are so easily effected.
Coil on plug are about the last thing but still a very good possibility.

[TxGreaseMonkey]

When I clean MAF Sensors, I only use MAF Sensor cleaner, not brake cleaner. Afterwards, I allow the sensor to completely dry out for 45 minutes. I also disconnect the negative battery cable, ahead of time, to force the ECM to relearn everything. MAF Sensors, like ICMs, are not cheap.

[TxGreaseMonkey]

Since kitch428 is a factory trained Toyota tech, try his suggestion of replacing the MAF Sensor first. If you didn't allow everything to adequately dry, or you used brake cleaner, it's easy to damage the hot wire in the MAF Sensor. One of these two ideas will likely solve your problem.

[basspaul]

Seeing as how I used brake kleen to clean the hot wire in the MAF sensor, I ordered a new one today. Will respond after changing it. Thnaks for your replies.

[basspaul]

OK. Replaced the MAF sensor to no avail. However, did get a P1133 and P1135 trouble codes. Replaced B1S1 O2 sensor and all is well. Seems O2 sensor was rather lazy and finally gave up a code. Don't regret replacing MAF sensor as I did clean the hot wire with Brakekleen and her truck does have 181,000 miles. Thanks for all the help.

[TxGreaseMonkey]

Good job.

[lennmorg]

hello I have a 1999 4 runner 4x4 I replaced a gasket in between the cat converter and muffler. Then I disconnected battery to clean and now it will not accelerate and it is sputtering. Any ideas