Stammering when first running

[gordinho80]

For past week or so, my truck has been stammering during initial run.

I start the truck fine, let it run for a minute before pulling out of the driveway. When I pull out, for the first minute or so of driving, it stammers and sputters. I'm thinking the fuel pump is on its way out. After the stammer, it smooths out and runs fine. Really not looking forward to replacing the pump! I'll probably cut an access panel in the bed when I do, though.

 

[badazzbulldog]

try the fuel filter first I just did a pump about a month or so ago in our 99 silverado and a week ago did the same thing yours is doing swapped the filter out been fine since

 

[98_k1500]

My 2500 is doing the same thing, it runs fine, then starts missing/popping out the exhaust, then all the sudden, she smooths up. It does it every time when its started cold. Im thinking the CTS may have a dead spot in it as it warms up or something.

 

[gordinho80]

Well, I tried the filter first. Replaced that a couple of months ago, no luck, still stammers occasionally right after cold start. I just got around to replacing the fuel pump, as I figured that could be the culprit. No luck, still does the same thing.

I'll fire up the truck, let it warm up for a couple of minutes depending on how cold it is out, then I'll start driving. I get out of the cul-de-sac onto a 40MPH road and it starts its little stammering dance for the first minute or so. Once it gets passed that initial little dance, its good for the rest of the drive.

This is more noticeable when the engine is cold and it is cold out. Could it be the CTS like 98_k1500 mentioned?

 

[gordinho80]

Anyone have any other insight into this?

 

[steampunk1375]

Test the coolant temp sensor for sure, all you need is a multimeter.

Which motor do you have? TBI or Vortec? If its in your sig I'm sorry, Tapatalk won't let me see it.

If its a Vortec I'd clean the MAF, test the coolant temp sensor to the computer, the guage uses a different sensor, and do a real fuel pressure check to look for the possibility of a failing pump or injector assembly.

TBI I'd do the same stuff but there's no MAF and the fuel pressure test would be to verify the pump and fuel pressure regulator.

 

[gordinho80]

TBI motor. I replaced the CTS on the top of the engine. It still sputtered after I started it and drove.

What really boggles me is that once the motor warms up a little, it runs smooth as silk.

 

[-sin-]

Search for "TBI engine sputters when cold"

http://www.topix.com/forum/autos/chevrolet-pickup-truck/T46TDE3QCQRNR7H2H