5.3L going into limp mode after 1 good mash of the throttle. Need Help.

offrd · Jun 3, 2012

It is a 2007 5.3 with a jims performance harness. After you initially crank it you can hit the throttle hard and it will roast a set of 42" iroks but after that it doesn't have any power. You can put it on the floor and it will hardly go. I have replaced the mass air, map, temp coolant sensors and has new o2 sensors. Any help would be greatly appreciated.

onetoncrawler · Jun 3, 2012

mine was doing the same thing - call

Lane Culver Automotive Specialties

247 McCutcheon Loop Rd
Laceys Spring, AL 35754 (3205)
256-882-2450

he fixed the problem with mine, its more than likely a tune issue :dblthumb:

TBItoy · Jun 3, 2012

Did you call Jim's Performance about the issue???

Limp mode is ususally a tune issue. Forgot to turn something off, or looking for input on something that was "supposed" to be deleted.

I think I'd have started there instead of throwing a bunch of new parts at it. :

matth_85 · Jun 3, 2012

You need to have it re-tuned. I had no luck with my computer from Jim's, and he was also very little help. He does a great job on the harness but the computer was WAY off on mine. Even if it's not a tune issue, with it hooked up to the program those guys use you can moniter everything and see whats up.

matth_85 · Jun 3, 2012

And if your using drive by wire it could deff. be an issue with the pedal, throttle body, or even wiring. The wires that go to the throttle body sometimes break down.

offrd · Jun 17, 2012

Just now had time to work on the problem and here is what I have found. I unplugged the pedal and plugged it back in and the motor performed great for about 15 minutes and then went back into limp mode. I repeated the same process a couple of times and it would work great and then go back to bad. Has anybody had this issue and does it sound like I need a new pedal, Im kinda leaning that direction but wanted some more opinions before I spend anymore money.

patooyee · Jun 17, 2012

What ecm? What pedal?

zjtrey · Jun 18, 2012

Did Jim's provide you with a list of what part numbers you should be running for the dbw pedal, maf, map, o2's and injectors? Im no LS guru but I've done some troubleshooting and these few things can make a big difference...