Check Engine Light Solved, Code 137, Hope This Helps Someone

[sammer1986]

I have used this forum and others in the past to help solve problems with my truck so I thought I would return the favor and put some information out there, hope this helps someone!
My truck had this annoying check engine light, code 137, and it kept hesitating real bad when I would try and accelerate. I replaced the o2 sensors and that didn't help. Checked fuel pressure and that checked out alright. I had recently done a tune up so I figured that wasn't the problem. I checked every vacuum hose I could see and they seemed fine. I was beginning to think there was a leak in the plenum gasket or something. I tried cleaning the maf sensor as well and that didn't do anything. It was a really annoying problem and I was at the point that I was going to tear down the top end of the motor and just replace everything lol. I finally found this article in the bowls of the internet where this guy said his ecm was bad and his symptoms matched mine. I pulled the ecm, not a big deal except for the bottom bolt which you have to get creative in order to get off, and pulled it apart to look at the circuit board. Sure enough, one of the diodes had come loose. I ordered a new one off ebay for 100 bucks and it fixed the problem!
I just wanted to put it out there that this can be the problem when your truck is having driveability issues, it is pretty easy to pull and examine the circuit board, it should be among the things you check. When reading the forums here and elsewhere it seemed to be something everyone assumed probably wasn't the issue. It may not be a common failure but it can happen and is pretty easy to check, hope this helps someone and thanks for all the help you guys have given me in the past

P.S. Not sure if it will show up or not but I have 1994 ranger with 4.0 OHV in it, 5spd, and its 4wd.

 

[alwaysFlOoReD]

Thanks.

 

[DeerWithIt]

Hello! Not sure if you're still active, but I'm desperate at this point. I have been fighting with the same issue as you. Bad hesitation on acceleration. I replaced nearly every sensor, valve, and regulator on this thing and nothing is fixing it. I pulled the same engine codes as well. Even took your advice and replaced the ECM. It still does it. It also doesn't like full throttle and it seems to have some kind of a spark knock under load. I'm seriously lost and need any help I can get.
1994 Mazda B4000, 4.0, Manual, 4WD
I have replaced:
Fuel filter
Both O2 sensors
TPS
MAF
Throttle body
EGR
IAC
Fuel pressure regulator
Spark plugs, wires, and coil pack
And the ECM

 

[alwaysFlOoReD]

This was his only post and hasn't been back since.
Sorry.
Maybe start your own thread and someone more knowledgeable may help. Link back to this thread if you do.