Have you had a fuel pressure guage on it when it stumbles and afr jumps up? If so, does the pressure stay steady? My thoughts are, if you were loosing pressure, ie. a bad pump, etc. that would cause it to go lean.

I have a FPG right on the fuel rail. It's pretty steady at 40 PSI....might shake a little between 39 and 40, but never drops by more than 1 PSI.

I should add, I don't drive this truck very much...every few months. I'm sure the gas is oldish, and I'm thinking maybe from sitting, one of the injectors is gummed up?

So, thought I'd update on what I found, and what happened to the truck:

The stumbling issue turned out to be a few things:

- cracked vacuum line to MAF
- three plug wires that were arcing due to high heat exposure at the turbo
- fuel pump was intermittently shorting out at the sending unit pigtail

So, after replacing the fuel pump assembly, new set of wires and fixed the vacuum line, she ran like a bat out of hell. So, I had a buyer lined up to pick up Dec 27th. I went on vacation last week out of the country, and on the 4th day, receive a call from our 23 year old son. He had broken into the garage, stole the syclone for a joy ride and wrecked it. If anyone knows these trucks, the cladding is unobtanium. Two steps forward, thirty steps back :(

Your son stole the truck or the new buyer? Either way, I am really sorry to hear that.

Son, stole the truck. Buyer will in all likelihood back out. Can't say that I blame them.

Either that, or offer you significantly less for it...... Is insurance going to cover any of it? The Typhoon/Cyclones are becoming VERY hard to find.......

Insurance won't cover unless I file a stolen vehicle report. Son doesn't live in our home but in an apartment we rent to him.

Robert, I am sorry to hear that. Most people have no idea how dangerous a 10 sec. vehicle is on the street. And before they know it, their in trouble. Hopefully there were no injuries, and hopefully it works out in the end for you.

Sorry to hear about the problem Robertmee. I hope the kid is OK.

Kid is fine....although I'd love to beat his a$$