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a little help? i just have tonight to try and fix the problem

luk3

1/2 ton status
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Apr 29, 2002
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idaho, USA
hey guys, im kind of in a situation, its not about a truck but i need information on this problem fast as possible since i have to drive 4 hrs to work tomarrow. the problem is my buick efi 3.8 v6 will run about 40 mins then act like its not getting any fuel accept on occasion ..so it jolts kinda and will hardly accelerate, but when i let the car sit it will run fine, it also runs fine when its not in gear. and idles great any ideahs or thoughts? sorry if its in wrong fourm i do realize it sorry again.
 
My 2 cents how bout a fuel filter / mabe a fuel pump just my 2 cents /forums/images/graemlins/crazy.gif
 
ya my first guess what filter, but y would this happen only in gear and after the engine runs for 40 mins?
 
Fuel starvation...the filter probably allows enough to maintain idle but not much more. As you drive it it begins to starve for fuel more and more.

I second the filter problem...(or third it /forums/images/graemlins/crazy.gif)

Rene
 
I go with the fuel starvation too, but with a twist. Sounds like after the engine heats up you get vapor lock. I think that's the correct term. In other words, the fuel turns to a vapor because the fuel line is too close to a heat source. You'll get enough fuel for idle but when fuel is needed for power there isn't enough vapor to supply it.
 
EFI rarely has this problem...fuel is constantly circulated through the system so it never sits long enough to acquire enough heat to vaporize.

Vapor lock is climbing up my list of things people think are a problem, but more often than not, aren't.
 
Check the exshaust! If the cat is melting down it will plug your pipes and kill all power. Does it sound like it's screeming the air out of it? I had it happen to me and it just sucked. Hope it's not it or your in for a long night /forums/images/graemlins/yikes.gif
 
I'd check 3 things.

First is the fuel filter.

Second is catalytic converter.

Third is the coil pack. The electronic part that is underneath that coil pack can sometimes quit working when it gets hot. I usually just grab the whole thing while I'm at the junkyard.

Also, ignition coils often begin to fail when they get hot. More noticeable when it happens to vehicles that have a single coil. Also, vehicles with a coil wire often have similar symptoms (but usually you can't restart when hot). Usually it's faster than 40 minutes though. A telltale sign of bad ignition is black smoke when it shifts gears (unburnt fuel).
 
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