My 96 Tacoma 2.4L AT. has a lack of power that makes it difficult to maintain over 60 without riding in 3rd gear. The tailpipe is also very sooty, leading me to believe it is running rich. So far I have or have had checked:
-fuel pressure (high end of normal)
-exhaust (no obstructions)
-MAF sensor (cleaned)
-tire pressures (good)
-cylinder compression (good)
I have replaced:
-spark plugs (properly gapped)
-both O2 sensors
-fuel pressure regulator
Fuel injector cleaner has also been tried to no avail. I did find a crack just below the exhaust manifold. I'm going to get that fixed soon. I'm running out of ideas for this thing.
I also always run it with a ScanguageII plugged in. I have never gotten any codes.
I just figured out that the dealership put in the wrong spark plugs. They put in the single electrode plugs. A sticker under the hood calls for dual electrode plugs only. I just replaced them the other day with no change resulting as of yet.
I also noticed that when I cover the exhaust with my hand it comes away wet, as well as black. So I held my hand slightly off the end of the pipe, and I could see small flecks of sooty water hitting my hand. I look under the exhaust pipe and see what looks like a sooty water drip trail on the underside. Upon looking inside the tailpipe, I can see water droplets coating the inside. Here are some pics of the underside of the pipe and the bumper behind it that is getting splattered.