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bad MAS?


I wanna be sure before i buy new one. 2003 taco 2.4L 2wd 5sp 73k miles(not a typo)

2003 Toyota Tacoma Factory Service Manual page SF-25 says 2-3 ohms at 68°F and 0.9-1.3 ohms at 104°F. I get consistent repeatable reading of 162k ohms on 200k DVM scale at 80°F. I cooled it in the fridge and checked the 32°F reading and I get a reading for under 1 second, then it goes infinite. Each time I try, it does the same thing. I get a reading, then it goes infinite. It should be 4-7 ohms. As it warmed up I was able to get a consistent steady repeatable reading of 194k. Then I reversed my DVM leads and its infinite, every time. Then I reverse them again and I get the 194k again. According to the service manual polarity don't matter, unless that's a mistake. Going back to 80°F test to check and I get 180k ohms and when reverse DVM leads I get infinite. That higher reading might be because it might be a little cooler then before. Not by more then 5° though.

Next day I get 186k at 77° and 1207k on the 2000k scale. Both times when i reverse polarity I get infinite. That 1207 tells me something about my resistance readings are not right. I just tried the 200 ohm scale and get infinite reading either polarity. I hesitated using the 200 ohm scale because the FSM warns about using full scale resistance readings because it might ruin sensitive electronics. After doing that my 200k and 2000k readings remain the same.

Is there something in my house i can test that should measure 100k to 200k ohms to verify that my DVM 200k scale ohms are reading correctly? It does read zero when leads are touched and I just found two 5 ohm resisters that both read 5.8 ohms on the 200 scale and infinite on 200k and 2000k scales.

I don't think dirty MAS would read high, would it? OK, I just sprayed it liberally with 70 percent alcohol and let it dry. Readings unchanged.

The symptoms don't point strongly toward the MAS. More so a dirty TB. I just cleaned the TB and IAC w/o removing from vehicle. First time cleaning since i bought taco new in 2003. So, yea I might need to remove to do a better cleaning, but before that I decided to test the MAS. This vehicle drives fine! Just idle sometimes slow and sometimes fast. Slow is more common, then fast. Idle always goes way low when release throttle. It usually recovers, but does stall once in a while, more so with AC on.

I think I need new DVM and new MAS. Ur thoughts?



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