Hey all. I got some strange issues with my truck. What happens is I'll be driving down the street or coming to a corner/ stop and all of a sudden the thing just shuts off. It always does this at low speeds and I'm able to stop and start it right back up. It also occasionally has a hesitation almost like the engine is missing but there is no bang (maybe it just doesn't fire?) and it almost feels like it's the trans. Also when it does this the trans will usually start acting up for the rest of the drive. Hard shifts, gear hunting all that mess.

Here's what I've done. I fixed some hoses that got rid of my evap codes. Replaced my o2 and added a defouler to make that code go away. Now all my check engine codes are gone and the truck still does it. Mind you some days it will be fine and others it just decides it hates me. Mechanics can't find anything. I cleaned the TB and no change. I will be replacing sparks soon as they are a little out of gap but they weren't fouled or anything.

The truck is an 03 5.7 2wd. 170k on it. Pulled the trans wire as with all 03's. No cat and some no name performance muffler. (This sucker is loud.)

I'm assuming it's a sensor somewhere but where should I start next? Do y'all think I should pull the valve covers and check my springs?

 

Anything guys? Another forum suggested I need a new trans. Could a slipping tranny cause the truck to shut off? It does slip in higher gears on occasion but I drove 4 hours round trip Saturday no issues. I wish something would just break instead of being so random

 

If no code is thrown it could be a faulty sensor, I would check Crank Pos, Throttle Pos, Cam pos

 

Also since your truck is a 03, its before the control systems switched to solid state, so I would check the ASD (auto shutoff) relay.

 

my truck has done the same thing (04 1500) usually it is from WOT to slaming on the brakes. never figures out what it was it just kinda stoped happening.