Ive been running my 03 5.3L for the past few weeks with the Maggie on with no issues.Getting on it with boost and playing around.Now tonight just stopping at a light the "check engine" popped on with "Reduced Engine Power" showing on the screen?So as limped it around the corner I shut her off for a little and turned it back on with the same results.So I disconnected the battery and got the reduced engine light to disappear.Just enough to get me home WITH the check engine light still on.Any suggestions of what it might be before I end up at the dealership to get it scanned tomorrow?

 

The code will tell the story.

 

I would scan it at the parts store instead of the dealership. They can look up the code for free.

I'm not real familiar with the maggie. Does it use a 2 bar MAP and tune?

I did my own 2 bar tune with the STS, and I was getting p0068 or p1514 (I don't remember which, i think it varies by OS), but it was called MAP/MAF correlation error. basically the PCM thinks something is wrong because the sensors aren't agreeing with each other.

IDK what else will put in limp mode.

 

Yeah...but I was hoping someone could maybe pin point the problem by saying "oh that happened to me and it was this..." but its vague I know.Guess Ill find out tomorrow.I have a feeling its the tune......

 

Broken ring landing with crushed electrode on spark plug causing continual misfire codes can cause limp mode ... don't ask me how I know ... Hope everything works out for you though.

 

An SSS came into the shop and had the same sympoms, the wiring that goes to the throttle body wasn't spliced correctly causing the low power/ limp mode. I just thought I would add that since you were looking for experiences.

 

the spark plugs have maybe 500 miles on them.And the weird thing is is that the past few weeks it ran beautiful.Down at the dunes in Pismo it friggin screamed up dunes and would spin all fours up to 50mph on the beach and after your were searching for your head that flew in the back seat haha.But tonight just cruising up to speed and stopped at a stop light,then ding ding ding good ole limp mode pops up.I could understand if I was rodding the hell outve it constantly....but its weird to be ***** footing it for a change and it lights up.Its supposed to be the other way around lol.

 

Get it scanned at Advance or Autozone first before you take it to the dealer. It sounds like the P1514. A lot of fi vehicles get this code


https://www.performancetrucks.net/fo...d.php?t=421738

 

My truck with an STS kit did the same thing. "Reduced Engine Power" would come on and I would pull over. It happened twice on my way home from getting it "custom tuned" lol. It was entirely the tune. No mechanical issues whatsoever. Now, what in the tune I do not know because I took the truck to someone else for tuning. I would take the truck, if possible, to someone reputable for tuning. Good luck...

 

Yes it was that code 1514A.Telling me that it was either my MAF and or my Throttle Body positioning etc. etc.But when I started it up this morning there was no engine code and it ran smooth.Though during the scan I did notice the LT Bank was at idle around 15% and with throttle it bounced around 10 to 13%.