Hi guys, you've always steered me right in the past, and I'm hoping you can help me with this all new problem.
The background - several months ago, the truck wasn't wanting to start. Just kept turning over and nothing. Almost like it wasn't getting a spark. Go out later and it would fire right up. Made some calls, and was told it could be the fuel pump, and that if it just kept turning over, I should thump the bottom of the fuel tank. I did this, and for awhile, that seemed to work, It finally quit on me while driving, and I looked into getting a new fuel pump. Cost was higher than I expected, so I found a used pump at a junkyard and installed it. slightly different top piece, so I pieced together the bottom of the new (used) one and mine, and installed it. Seemed to fix the problem, but noticed uneven or rough idle now and again. However, the most frustrating thing was that, when accelerating from a stopped position, the truck just had NO power. Almost as if the transmission was just not engaging fully. Once it got going, it was fairly normal again. Even more interesting is that when it was idling a bit rough, that is when the no power issue would happen, but it had bouts of normal idling and acceleration from a stop. It's had the check engine light on since I've owned it, and at one point in the past, I got it checked, and it was some sort of oxygen sensor or something that the guy who checked it said was not a big deal. Well, now, with all of the new problems, I had Auto Zone check it again, and it came up with the code "Internal transmission failure". We even cleared the code and did it again, and it came right back. I am in NO WAY a mechanic, but here is my question - If the truck had NONE of these lack of power or rough idling problems before changing the fuel pump, but had them immediately after putting in a used one, doesn't it make sense that the pump HAD to be the culprit? And if so, why in the world would the code read as an internal transmission failure? And lastly, what in the world should I do from here? It would be nice if I could just change out the pump with a new one to see if that solved the problem, but if it doesn't, I'm out over $600 and still don't have a good running truck. I'm just frustrated as all hell, and no idea what to do. I MISS MY TRUCK! Thanks for reading, and I apologize for being so long winded.

 

Fuel pump replacement and trans failure are probably not related. Just a coincidence. Unless you knocked off an electrical connector from the trans, while working on the pump.

What was the actual code you pulled?

Were there any other codes?

When does it idle rough? As soon as you start it, or after it has been running for a few minutes?

When was the last time your truck got a tuneup?

 

Verify fuel pressure properly with a gauge first. Then do a search here for plenum. The fact you have o2 sensor code(s) leads to a plenum failure and bad cat and o2 sensors.

 

If it turns out its a fuel pump issue with the lack of power and rough idleing, look on Ebay I got a brand new complete fuel pump assembly for $80. almost a year ago. The issue with my fuel pump was volume not pressue, but this is probably not related to the tranny code, unless the computer is gone into limp mode because of lack of fuel pressure or volume.

 

What i would like for you to do is to unplug the transmission 8 pin connector just in front of the rear cooling line.....The shifts from 1-2-3 are controlled by an electronic governor circuit.....By unplugging harness you will have MAX gov pressure if all is good...The idea is if you have 1 st gear in Man1 , 2nd in man2 , and 3 in OD position, it would seem that trans is ok and whatever shares the same ground as the governor pressure control solenoid could be worth a look.....If the gears do not shift manually you indeed have an internal problem , perhaps a bad/stuck Gov solenoid....


Brian