Alright, so this is a weird one, It first began with my father driving it, at a stop sign he took off and started going, but it stopped running completely, NO BUCKING of any sort but it started back up within like 3 seconds?

Alright, I finally noticed it while driving. Going onto the on-ramp at the freeway, about 70MPH and I was floored to get into traffic, when I let off the pedal to slow down the truck completely hit 0 RPMS, I think the O.D. Light came on but cant guarantee that due to glaring. But it was as if it just completely died and started rolling, MPH still showed the speed slowing decreasing ofc. But then about 3-4 seconds it picked back up. So I decided to floor it again to see if I can make it happen again, and guess what!
I let go of the pedal at 75MPH from flooring it, feeling like it shifted rough or was shifting funny and it stopped again. It went back to 0 RPMS and just started rolling down the road slowly decreasing, no response on the throttle or anything at all, then about 3-4 seconds it picked right back up and had response again.

What could cause this problem?? I have done new Injectors, CAT, Fuel Pump, Tranny was rebuilt. Engine has no leaks, new water pump/Timing chain and everything was done properly. Runs like a champ. Stong and steady, I have noticed I hear a really loud Hiss when accelerating or like a clicking/ticking noise under the steering wheel or driving side dash. I've tried looking for it but only ticks while driving down the road.

 

Check the crank position sensor. When they start going bad they can cause the problem your having.

 

I already replaced that, and usually the crank would make the vehicle run like crud all the time. not just shut the vehicle off.

 

Swap the ASD and horn Relays in the PDC, see if that helps anything.

 

I tried swapping out the ASD and researched it, that was a good suggestion, but I have no idea why the horn relays would cause an engine to shutoff. So.... My horn works and the panic button works. So I dont believe the horn relay would have anything to do with this as its dedicated for the horn/etc.

Anymore suggestions?

I did a Noid check, plug check, wire check, compression check, fuel pressure check, and a vacuum check. all good.

 

It's not about the horn relay causing the engine to stop. It's about swapping a presumably good relay (the horn relay) with one that is suspect (the ASD relay) in order to determine if the symptom picture changes. If the fault follows the relay, the relay is bad. If the fault doesn't follow the relay, the relay is eliminated as a potential suspect.

 

Alright well I put a new one in and didn't resolve the problem.

I am gonna place a new cap n rotor in it as a factory cap/rotor. and check my IAC valve and see if its working, if anything check the plug for it as well.

 

Alright, So I replaced Cap and Rotor. Old ones looked good anyways. I covered all Plug wires with Split Tube to makesure no crossfire. I let truck start up and it idles rough, but once warmed up it runs fine. I know it runs pretty cool, so I don't know if that'd be an issue or not? Never reaches full 210 Temp anymore with the new Thermastat and the new water pump I did. I also did the plenum and intake gaskets so I don't have oil/fuel mixed in the intake, I Do not lose coolant or oil at all. None, So thats a good sign, I do know my oil pressure runs a little higher but once warm it tunes down but not a huge amount more of pressure. Maybe 1/3 or 1/4 more then the middle of the gauge?

Actually, could a bad Oil Pump or a Coolant level temperature sensor cause a problem like this?
I was reading a post that someone stated if the coolant is cool, the injectors run more fuel to try and warm the vehicle up? I dont think this is the case, do to the fact that my fathers truck is the same truck and has the same thing after his water pump/etc.

I dont have shorted wires anywere or bad grounds, I hunted everything around the engine and shook wires around, checked sensors/etc. Basically all there is left to check is valve clearance. But I don't think this is a mechanical issue. Its more of a fuel issue or an air issue, too much fuel or not enough air or something of the sort. Too Lean and dies out. Heck I unplugged the IAC on both my truck and my fathers and it doesn't do squat to the idle.

So thats not the problem. All my Injectors are new and ticking. I just wonder what this could be, small stuff like this for my vehicles bother the heck out of me. Tomorrow i'll be routing my Fuel/Air Mixture Gauge so maybe I can get it plugged in and going tomorrow to see if thats an issue. Never know. (As well I will run a bottle of seafoam in the vacuum lines and see if it clears anything out. I doubt it, When I had everything opened up it was all clean and shiny. But Could possibly have something stuck in there that I don't know about and I will put some inside the fuel tank.)



Suggestions appreciated! I'll let you know if I've done it already Lol

 

Have you checked the throttle position sensor, or the map sensor ?. The map sensor is used to control timing and fuel delivery, so if its bad it could cause the problems your having.

 

Wrong thread...