Yesterday, after driving 10 miles to work, had to go pick up parts. On my way back 2 minutes after restart, lost accelerator pedal response. I could only get about 1500 rpm then nothing. When it would rev to the 1500 rpm the CTD was rattling, but no smoke. Drifted to a parking lot did a restart. It would rev normally all the way. Put it in gear and move the CTD would go into this rattle and the pedal response was gone again. Again with a restart and I parked the truck on a steep incline in both directions to see if maybe lift pump but when truck was parked and not moving it would rev normally. Did not have my tools to try an apps reset. So I checked the filter for any leaks and the hoses from the turbo looked normal. Finally I just started switching the relays in the fuse control box. Truck finally started and ran normally. Drove it 15 miles to the dealership with no problems. Thay had it for the afternoon, said there were no codes, the fuel pressure was normal, and they test drove it for 7 miles, and just have no clue. I drove it today no problems. Anybody have an idea what happened? And did I "fix" something by switching the relays around? I got rid of a Chevy 6.5 that was unreliable and I don't like the feeling that this could strand me with a full load somewhere. Oh, the temp was 32 degrees and this truck has been running and starting no problems down to -7 over the past weeks. I had run over 125 miles on the last fill up. I use Rotella anti-gel fuel additive, Hess fuel. Any comments would be greatly appreciated.

 

First thought is that you switch a bad fuel pump (LP) relay around. It might of had a poor contact or loose connection...

 

I have since run another 100 plus miles everything normal. Just going to run this tank low and refill. Is there a relay that effects the lift pump? None of the ones I read of the fuse box lid seemed to mention fuel. I asked the mechanic at the dealership same thing and he said he thought the pcm ran the pump. My 6.5 Chev. had a lift pump relay and I always carried a spare as it went sour twice on me. Again if anyone has a thought on this please post. Thanks.