Cutting out when I hit the gas

[k20]

Cutting out when I hit the gas *Update*

Does it ever end? Tues discover axle seal is leakin, then today, after spending all day working on nerraw117's blazer, on the way home, sit at a redlight, then I hit the gas and it cuts out and kinda chugs, then takes off. Only did it 3 or 4 times. I switched tanks to see if one was out of gas perhaps and my gauge just messed up, but it did it on both tanks.

I have 1 electric tank in each pump, and then a supplemental pump on the framerail. It is either the supl pump dying, the fuel filter clogged, ignition module, or coil, imho. The ignition module is a maybe, but when I had em go bad before, they would always misfire from a stop, not just 3 or 4 times like this one did. The CEL never came on, like an ign module was bad, and it set a code. Coil, Im not sure about, never dealt with a dead coil, but I think it would just die and not spit & sputter.

I havent had time to diagnose at all. Gonna check tomorow and see what the fuel pressure is running at. Im hoping its the fuel filter, but just wondering if any of you have ever had this problem and if you had any more ideas what it could be.

Finally, could it be vapor lock? I kinda doubt it, since its FI and it has a return line, and it wasnt that hot. But is that possible? I mean last yr, I could sit & idle in 100 degree weather and never had a problem with vapor lock, and I havent moved any lines since then.

Thanks for any help guys. Chris.

 

[offroadnut]

love to hear what the problem really is with yours. I have a 90 Sub and when I went offroading it would start to do that when I got in a heavy load... it would chug and spit and almost die(if I didn't let off it would die). but on the road it is usually fine. I had it do it once when I was putting my foot through the floor at a light taking off. I just got this truck about 2 months ago and it only has 90k on the mileage. I hope it is something easy...

 

[diesel4me]

lots of things can cause it....

I see a lot of the newer GM's with the dinky distributor have cap and rotor problems a lot--a few had no visible defects like carbon tracks or cracks,but ran a lot better with new ones--might not be your problem though,unfortunately the only way to tell is to buy new ones,or swap another known good one on,the drive it and see...they dont always act up ALL the time,it can change depending on the weather...is it worse on damp or rainy days??

Any possibility of water in the fuel??--I have heard some gas sations had some fuel delivered with water contamination here recently--I would not doubt the fuel we get isnt the best quality since prices rose..try some isopropanol dry gas and see if that helps..it will run worse cold than hot if water in the gas is the problem,but it wont go away completely either..

The other things you listed are all good possibilities too--time to start the process of elimination..

 

[k20]

It did it on both tanks, they were filled at diff stations on diff days. Yesterday when it was doing it, it was bright & sunny & warm. And it didnt start doing it until the truck warmed up. I had gone 5-6 miles before it did it the first time.

 

[k20]

Well today, it didnt do it from a stop. Had left a redlight, turned left, and started going straight, and knocked it halfway to the floor, it did the little spit & sputter deal, then it jumped up & took off like a turtle with his shell on fire. Anyway, this past weekend changed the fuel filter & the ignition module. Seems to idle better and hasnt done it from a stoplight since, just today when I punched it that one time.

Could it be spark plugs getting used up? Big blocks love their plugs, and I havent taken the time in the last, 5,000 miles or so to clean em or change em. That a possibility? I would go pull a plug now, but its starting to mist/rain again .

Thanks guys. Chris.