Shutting down

[Aerial]

I just bought a 200 Mack rd688 e7 350 using it as a debris loader truck. I recently had the brake lights fixed rewired and soon after my truck started shutting down while driving down the road. If left in gear it will pick its self back up and start running again. The problem does seem like its getting more frequent. The truck will also shut down while at idle turn the key fires right back up. Checked fuel filters air filter and the normal easy stuff but to no avail. I'm wondering if anything may have been broken loose during the light fix I.e. grounds and so fourth the truck does seem under powered I even lose mph climbing a small hill while in top gear empty. 

 

[juststeve]

You may want to replace the speed sensor located on the back of the transmission. I had something like that happen to mine similar to that.

[sllimec47]

Did you figure it out?

[LilMartian]

Is the shutdown lamp coming on? Red circle with an X in middle, when it does it and may want to make sure it works. Usually 3 Amin shutdown causes are oil pressure, coolant level and temp if turned on. Have seen oil pressure sensors cause the problems and with an rd, the gauge is mechanical with an extra oil psi sensor for the ecm, located on top or side of oil filter housing or stand. What you can try is, unplug the oil psi sensor when it starts to do this, changes the code from a mechanical problem to an electrical and will cause a shut down, but most of the time it will run for awhile. Also, if male lamp comes on and you can catch it when your not driving, flash code by turning cruise on/off switch off and pushing the set down then up and count how many flashes. Maybe that will help figure out problem for you