I need some help.. I am in Missouri and need some advice and the stealerships are closed today....

While leaving on a 600 mile trip yesterday (AL to MO), I was 250 miles from home driving in a SEVERE thunderstorm..... when all of the sudden the truck went into limp mode.. No CEL just limp.

Called On-Star and I had P0401, P0404, P0405 and another P0404. (I know, all releated to my EGR plate).

Limped to the next town, went into Autozone shut off truck and when I get back outside to scan with OBDII and they found NO codes.... WTF??? When pulling out of Autozone, I noticed the truck was now running fine....

So I decide to drive on..... Got to St. Louis and DAMN.... limped again..... same codes..... again, WTF!!!

Pulled over, did MANY ignition cycles to no avail..... Finally limped into my destination at 12:30am... get up this morning to look at the truck.... DAMN! No Limp!!! WTF!!

I have had my EGR mods done for 10K miles with never a CEL or limp. So this prompts a couple of questions:

1. Since I am running the TxCAI, could the rain have caused the codes? and how can I fix on the road?

2. Why/How is the truck going in and more importantly, coming out of limp by itself???

Thanks for the help.

ttt

I have never seen those codes by themselves go into limp mode.

Normally a P0299 in such a situation is to blame (need to look at history of codes).

What are you using to stop coding with a blocker plate?

Thanks for the response Pat.

If you are asking how I have been blocking/clearing the codes. I haven't. (no fingerstick, Pred or EFI) I have had no issues up to this point didn't think it was necessary becasue I have a Federal truck

On the trip up, I had the codes read by On-Star. When I read them at Autozone they used a Acutron. It picked read NO codes.

I do not have no CEL light... just limp.

They used their Acutron to clear codes... It gave them an error something like, "You have no code, proceed with erase?" I choose yes and it "fixed" the limp...

Funny thing happened this morning, I got it to limp when applying WOT several times. (IIRC, this is still symptomatic of the EGR mods I have completed). The thing that throws me off is why it has taken so long to limp...

I know the long term fix is the updated firmware from the stealer and/or Live EFI... I will be placing an order next week. I am just concerned about making the 600 mile return trip in heavy traffic...

Thoughts?

It shouldn't hurt anything to drive it.

But granted the limp mode is going to irritate the heck out of you.

There is also a possibility it's an undiagnosed P1093 which could be due to a restricted fuel filter.

Some ideas if you really need to fix it on the road:

Try to replace the fuel filter (might have no effect)
Experiment with unplugging the MAF sensor. Not sure if it will help, shouldn't hurt to try. If it's a P0299 limp (boost error), having the engine not see the MAF might keep it from coding a 299.
Try to remove the blocker plate.

Sounds like you might be on the right track. Removed your MAF sensor and set in in the sun and let it set for a couple of hours and dry out. A few of my
the guys I know had the same problem and this fixed it. But from what I've seen and heard on the TXcai getting water in the intake is almost impossible. but you did say the storm was severe so this might be the case. Hope it fixes your problem. Good luck.

Thanks for the replys guys...

Sorry for the slow reply, I didn't have internet connectivity.


Anyway, here is an update:

Went to Autozone and scanned with their scanner... No codes. (even though I was in limp) selected erase codes and truck ran fine.

Drove back to the hotel and examined the air filter. (I agree that the TxCAI didn't induce water but my thought it might have been possible through the stock opening.) Either way, it didn't feel damp or wet but looked slightly dirty so I changed it...

Also of note: noticed the insulation under the hood had water stains behind both headlights from driving in the storm..

Headed back to Alabama yesterday...... no limps. I can't figure it out.

If the airfilter was the culprit, wouldn't I have a code related to airflow?