1992 3.0 with auto trans. 260k miles.
Spit sputter "misses" only at 1800 to 2000 rpm after warm up. Worse on hot dry days but smooths out when driving in rain? Has new plugs, wires, rotor and cap. I've read about 02 sensor, coolant sensor and maf. I do have a donor vehicle available but it's a 1991 manual trans. Soaking 02 nuts on both vehicles now with pb oil. Are these sensors interchangeable?
The 02 sensor should be replaced periodically I've read. O'riellys sells for $85 and there are many listed at Rockauto $25 and up...which one?
Am I even on the right track so far?

 

Just make sure the 02 sensor is Denso.

 

I go to www.sparkplugs.com and you can get the part number for an O2 sensor from them. Then I search different sites such as ebay or Amazon for the best price. Get the exact fit. The O2 sensors should be interchangeable but double check.

In my part of the country, the exhaust shops are really familiar on replacing the sensors in your pipe. Most are so rusted in the pipe that they will just remove the old sensor and install a new bung for the new O2 sensor. It cost about $25 for me to have it done.

As far as running better in the rain, that can be a tough call. One thing I would do is find a dark shop, alley, road and with it running and the lights out on a damp and dry nights and look under the hood while the motor is running and see if you have any little arcs around the motor.

Other wise I really wouldn't know other then to start testing components, looking for air leaks or anything that would be affected by damp air.

 

Removed 02 sensor and "sniffer dome " is dented, don't know if it matters. Ordered a new denso. The 1991 was different.

 

Installed new Denso 02 sensor. It made an improvement but still have the 1800rpm "stumble" ...just not as bad.

Can't see any arcing under hood btw.

Next question, can I swap the 1991 MAF with the 1992 ?

 

On the top of the AFM in the black part, you will see the part number. Compare the two. On the earlier generation it is part number 22250-35020. You could also see if the part number is the same on toyotapartseast.com

 

The part numbers matched so I swapped them. It made another improvement in the low rpm range...but I still notice (some) hesitation @ 1800-2000rpm 2nd to 3rd gear change.
Have to live with it I reckon.
260k miles on the ol gal...I'm just lucky to ride home huh.
Also installed two TPS, one new and one off donor, no change.