Hey gangGot a guy here with an 07. He was asking me if I had ideas on his issue - details belowRuns a straight back exhaust - no DPF/muffler etcRuns a Edge Comp Race ...... on levels 1-4 whilst towing .... truck "chuggs/misses like its running lean" - his words.On Levels 5-7 its fine.Happens in OD or without OD and he doesn't think its EGT/Boost defuel (my first thought).Edge say its not the chip ......... My question is why OK on levels over 4 (like 5-7).Lets here some ideas - will pass them on - thx for help

What does it do with the chip off then? Or is level 1 stock?

What does it do with the chip off then? Or is level 1 stock?

I think he said something about still problems in stock - but in stock it thinks the DPF etc all installed still ....... not sure - will ask. But why would all be ok on levels 5-7 ............... not 1-4

Any unusual smoke? Any Gauges? Any error codes?

Sorry guysWell ...... appears I didnt get the whole storyBit confused me was he said it only had issues on levels -14 but not 5-7 or whateverSo since then he has taken to mechanic - who thinks it is the chip. Happens on all levels ...... and I do believe throws an injection code with teh chip on. But no code with it off running normal.Sorry fella's ........ was trying to help him out ...... but guess it helps to have all the info.

Well it sounds like the chip is to blame... If the chip is turned off and it runs fine then flip the chip on and it gets crappy then the chip is to blame pure and simple... The only thing else I can say is check the lift pump pressure it might be too low of fuel pressure and starving the rail out...