A few months ago I posted a thread whereby I discussed a problem I was having with my 2003 GMC shutting off intermittantly. I took my truck to the shop where the diesel mechanic said my truck was experiencing fuel line collapse that was causing vacuum build up in the supply to the fuel filter. This was evident by noticing that after the truck would act up and shut off, the primer piston would be sucked down due to vacuum build up in the line.

So, the GMC garage replaced all the rubber lines on my truck and off I went. I was ok for about a thousand miles and now I am experiencing the same problem. The truck has shut off several times on me now and each time it is shutting off in a very predictible way. I can run on the freeway for an hour or so at average freeway speeds with no issue. Then, when I exit the freeway, I can go maybe a mile at most----then the truck will shut off. It's done this five or six times now----each time after having run on the freeway for an hour and shutting down following my exiting the freeway. It's beyond frustrating.

When the truck shuts down I had noticed that one of the freshly replaced fuel lines (work performed by a certified GMC garage) on the drivers side of the engine seemed to be flattened out. I would disconnect one end of this line, break the vacuum, reprime the filter and the truck would be off and running for some period of time. However, once I would run on the freeway again for an hour or so, the same problem would happen again following my getting off of the freeway. I would get the truck started again by repeating the process I described above. No fun when the truck shuts down in an area when you cannot pull off to the side of the road.

The line that seems to be the one that is collapsing was a rubber hose that the dealer connected with hose clamps. It had a pretty tight bend in it that caused it to flatten out somewhat (egg shaped inside rather than being round) when it was in use. I replaced this line yesterday morning with a section of braided line that is somewhat stronger and more resistant to collapse. I have not run the truck since I did this replacement.

The GMC garage said that there was no restriction in the line anywhere and that the problem I was having was due to collapsed lines(the truck is a 2003, so the rubber lines were old). However, their replacing the rubber sections did not solve the problem.

Does anybody thing that perhaps the problem was due to the line I replaced with the braided line being just kinked too much due to improper installation? I am half afraid to drive the truck anywhere at this point.

I know, I know, if I put a lift pump on this shouldn't be an issue, but it really shouldn't be an issue anyways with new lines, right? I am fairly disgusted at this point.


Also, does anyone know where I can purchase braided steel lines that I can use to replace ALL of the rubber fuel lines on the vehicle? It seems to me that these would be much less susceptible to collapse.

I am just looking for input regarding this reoccuring problem. It's been a real pain for me as my truck now is totally unreliable insofar as I am concerned. I live in the Los Angeles area and the truck shutting down in the middle of an 8 lane freeway is a hazard that I don't want to deal with anymore. Any thoughts on the matter would be most sincerely appreciated. Thanks.