Surging/Thrusting Problem Under Acceleration

I would try another "known good" ECM. In other words a brain from a "good running" truck.

 

$375 + $50 core charge. NAPA # NEC XTP21880 seems to be it if you go reman.

 

Dude sounds like if he's wrong, you don't pay.

 

Is the shock coming through the insulation on the wire or is it coming from the plug/some other metal part? It could be that in compressing the wire you are getting closer to something metal and that's where it's coming from.
Sounds crazy, though!

 

wires are pouched.

 

Could this be your problem? I don't remember if it was ruled out

 

Fingers crossed!

 

Be nice if that really was the answer. $30 will tell you.

 

I do admit it would not be unusual if that is your problem. You should NEVER feel a shock when you are touching a wire. All the diagnosis we have been working on so far has been by your replacement of parts you had mentioned, and the assumption that they are working properly. lol. No way of being able to tell if they are bad. That is one of the reasons it sucks with a difficult problem with not having the truck. I have one of those big ass OBDII scanners at my shop here, and it is worth it's weight in gold. If you do have one of your new plug wires leaking secondary spark, then under load it could DEFINITELY cause a lack of power, and may be perceived as a surge. Man I had hoped that the FPR would have been the problem. I think that is the first part I have suggested to replace. I didn't mention a Tundra because I didn't know you HAD a Tundra, and to be honest, I wouldn't have known they had the same FPR unless I looked up part numbers. At least now we have that issue out of the way. You wouldn't happen to have a GoPro on you? I am thinking at night you could mount it under the hood, pointed at the engine. Then, when driving at night, and under load, you could look for signs of arcing.....

WOW, Just after typing that statement made me think of a possible thing. EMI! Check the routing of your plug wires. If they are ANYWHERE close to the harnesses that runs in the engine bay, and the plug wires ARE "leaking" spark, they could induce EMI into all sorts of sensor signal wires. If you shock yourself at idle, imagine what the leakage is when under load at 2500 RPM? Since you DO shock yourself, I would replace the plug wires anyway, period. Get a decent set and make sure that you lock them in good. Even if that is NOT your real problem, you should replace those wires.

 

oh dang!! the gremlin may have shown his face...ive had this happen on a piece of equipment before. small tiny tear in the boot and it was arcing to the block every once in a while. Hopefully this solves the issues

 

I had that thought, as well.
Another thought, I had my engine mounts fail after about 18 years (170,000 miles), which caused the engine to sag into the radiator a little bit but only when the truck tilted forwards. Perhaps 2500rpm and sagging engine mounts could cause the engine to move in some way that the plug wires get close enough to something to arc, hence only causing the problem at a medium load. I realize your truck is not as old as mine and I don't know if this is feasible at all, but given the jumping hits it has taken I think it'd be easy enough to check.

 

jason upgraded to solid motor mounts awhile back

 

Ah, well then that rules that out

 

I hate when I see a problem with a truck and I can't get my hands on the truck to run my tests! GRRR....Let me know what you find when he arrives.