My dad purchased a 03 Lightning from a local GMC/Buick dealership less then a month ago.

Mods: JLP intake, Flowmaster catback, smaller pulley and Diablosport Predator 91 Pulley tune. (All mods on truck upon purchase)

We tracked down the pervious owner (personal friend) and he gave us the tuner.

The truck runs fine when he is just daily driving it, untill he gives it WOT then the truck revs up and seems to be missing (or hitting a rev limiter without shifting)

The truck has no CEL, but when we pulled the codes off it. It brought up 4 codes (P0602,P0605,P1211,P1690)

I know these codes mean:
P0602 Control Module Programming Error
P0605 Powertrain Control Module ROM Test Error
P1211 Injector Control Pressure Sensor Above / Below Desired
P1690 Wastegate Solenoid Circuit Malfunction

The first two codes seem to point to the truck's computer being fried and the last two codes seem like diesel codes???

We flashed the truck back to stock and still have the codes on the truck, and even stock it is still acting up under WOT.

What should we do next???

I did some searchs and found out that these same codes pop up on other Diablosport Predator tuned Fords (Mach 1s, Marauders, Terminators, and other Lightnings) but they all seemed to be dead threads.

Any help would be extremley helpful.

 

Makes it sound like the PCM is not happy, especially if it is still hapening with the stock tune.

I would caution against running WOT with the stock tune and a pulley...that may not be good.

As for the missing up top at WOT, plugs/plug gap would be the first and most likely culprit.

 

THANKS!

I will tell my dad to check that next. He is thinking it is a supply and demand issue so he added fuel injector cleaner and is changing the fuel filter.

Should we just take the truck back to the dealership, and raise hell (not mentioning anything about a tuner, of course) since they sold us a tuned truck, and it is still inside of 30 days????

And let the dealership drop the money on the 'goose chase'???

 

You could try, but my guess is they'll never figure it out.

Buick dealer techs are not the people I'd want messing with my supercharged/boost added Lightning

Pull the plugs, if they look OK, make sure they are gapped down to .030 or so, and put them back, if they look beat up, its cheap insurance top replace them

 

I will pass that info to my dad, Thanks a bunch.

Any tips for the plug replacement on the lightning?

Did the plugs on my old 4.6 and it was a PAIN! I imagine it is worse on these...

Thanks again.

 

Just use some patience and some lube if needed, dont let them bust off in the heads.

And make sure theres no water sitting down there before you pull the plugs out...

 

Am I the only one that had to re-read the first line....

Thanks for the help. I'll let ya'll know what we find.

 

Patience and lube will get you everywhere in life

 

Any other ideas out there?

I have posted this on other sites (Mike caught me on one) and the Ideas seem to be clutches in the tranny, fuel problems (filter, injector(s), pump, etc.)

What else could it be?

We are taking it back to the dealership, since my father lacks the disposable income to throw money at the truck in an effort to fix his 'new' truck.

 

Spark plugs are going to cost $10 and an hour of your time

I can't imagine where the tranny idea comes from, but I'd exhaust all other options before looking there.

 

The plugs don't bust in the 03's, those are the ones that like to blow themselves out.

 

My 03 4.6 blew a plug out.... Twice, diff plug though!!

 

this truck needs a tune up and a tune at the very least

 

My dad showed up yesterday and had me run the Lightning to get my opinion before we took it to the dealership.

Right the truck is on the stock tune, mind you?

I drove outta town to 'run' it.

The first time I hit WOT, the truck downshifts and revs up REAL fast, super charger is screaming, but once the truck revs up it never shift in to the next gear, just kinda hitting rev limiter, and violently shaking.

So I back off.

Then I try to ease into WOT, and that would alot better (no violent shaking)

But something is still wrong.

I now try from a dead stop, WOT, very little burn out, no shaking, look at tach it is reving and shifting (harder then stock should, imo) boost guage is pegged (past +10psi) but it does not seem as vicious as I remember this truck being. I look at the speedo, it is accelerating, but not mind blowing.

I repeat the test at many different speeds, I never get the violent shakes again, but the truck sounds like a monster, but doesn't feel like a monster....

We go back to the house and I use the Pedator to verify that it was on stock tune and check for codes.

The truck is on stock tune, and when I check for codes, a handy little "NOTE:" pops up before showing codes. This "NOTE" tells me that P0602,P0605,P1211,P1690 are all totally normal for tuned vehicles.....

And I click 'continue' to see that it has a P1000 code as the only code on right now.

I know that this code is 'normal' for a freshly tuned vehicle (stock or modded tune) and is supposed to go away after like 50 miles. My dad travel 220 miles to get to my house and how been on stock tune since last Friday. So he has put more then 50 miles since the stock flash.

 

So NOW the issue is that

*the truck did not upshift (once that i've seen but Dad said it had been WAY more violently shaking before)

*it just does not seem like a rabid pitbull (i.e. breaking tires loose in a dangerous fashion, gaining MPHs at an alarming rate, etc.)

*as it megerly and mildly does accelerate the Tach is moving fast and the boost guage is pegged, it has a mild 'miss' under WOT. Nothing major felt by the driver, unless you you really know what you feeling for. There is a slight 'hesitation' that can be felt and heard under WOT. The average person would not notice it but my dad and I can hear and feel it.

HELP!!! It is killing me.