Engine Running Roughly. Diagnostic Code 120. 1994 Mazda B3000 v6

[Research Rat]

I have a 1994 Mazda b3000 v6 that's running a bit rough. When moving from stop (clutch pushed in) to first, the engine has some hesitation after pushing on the accelerator and once moving, the engine does not accelerate smoothly. I've also had some intermittent issues with the motor continuing to accelerate after I've let off the gas. I'm the third owner. 100k mileage on the truck.

I went through running the engine diagnostics today. The throttle linkage appears to be operating freely and is not catching on anything. During the KOEO test, gave a system pass, but did pull code 120. It did not pull any codes in the KOER test and gave a system pass.

According to the manual, code 120 has two definitions:
TPS out of self test range.
Or
Indicates throttle position voltage inconsistent with MAF sensor (when applicable.)

After running the diagnostic, the engine ran smoother -ie, issue went away. It's done this in the past, where disconnecting and reconnecting the battery appears to clear whatever issue is ongoing, but then the issue returns soon after.

Any thoughts on what this means? The diagnostic pulled code 120 only, and no other fault codes for either sensor. I would think that if either of the sensors was faulty, it would pull more specific codes? Could this be a timing issue (1994 has distributor cap?)

Thanks in advance.
-Scott

 

[Research Rat]

Bump

 

[Earl43P]

Test it:

http://www.therangerstation.com/Magazine/winter2009/throttle_position_sensor.htm

Replace it if bad.

 

[Research Rat]

Thanks Earl.

Test it:

http://www.therangerstation.com/Magazine/winter2009/throttle_position_sensor.htm

Replace it if bad.

 

[helpme]

I would check...

and clean your IAC valve first. Its located right there on top. It a common problem.
I had to clean mine once and replace it once. I've got over 200K on mine.

 

[mitch4712]

I am having this same issue. Did you find a fix?