got a hic-up

Woody1 · August 20, 2003

Awhile back, bout 10k miles ago, I changed my plugs (01 GMC 8.1L) from factory to champion "Truck plugs". Question I got is, after it runs for awhile, and I pull to a stop light, I can feel it best I can explain it is that it feels like a hic-up. Not very noticeable, no-one else notices it but me, but its there. Is this due to plugs? or something else going on? got 46-47k miles on it now. Runs fine, no loss in power and doesnt do it other than at idle at the light. Got a K&N,Borla cat back on it too. It has just started doing it in the past few weeks. I mainly run this truck over the interstate now, cause I bought a wrangler Jeep to run around town with. Oh--- about a year ago, fuel pump went out, and was replaced under warrenty. Hic-up doesnt feel like it did when pump went out. Any ideas?

Hacksaw Hilliard · August 20, 2003

Are you sure it's the engine and not the transmission? I've had this "hiccup" too. Mentioned it to the dealer but they couldn't find any codes nor could duplicate it. I've got 21,000 miles on the truck and it's only done it a few times with no adverse effects.

Woody1 · August 20, 2003

nope,not sure. feels like the engine tho. its not a surge, its a "hic-up drop"

Woody1 · August 21, 2003

btt

MCourson · August 22, 2003

That same thing happened on my 94 after changing the plugs. I think that mine was caused by being to rough on the plug wires while trying to remove them from the plugs. Put a new set of wires on it and it has run fine since.

JimWilson · August 25, 2003

Well, I don't know if I have the same problem that you do but I have felt the truck idle a little rough when sitting still. It will be running as smooth as silk, then all of the sudden it will start to shudder a bit, then it will go back to "normal". Of course the dealer can never find anything wrong with the truck (they look at me like I'm some kind of lunatic, as though I really want to be sitting in their waiting room for hours while they jerk me around ).

Woody1 · August 29, 2003

anyone else got an idea?

350vortec · August 29, 2003

I would try new plugs by ac-delco what comes in it from the factory and see if that helps.

toddgotfish · August 29, 2003

I HAVE THE 5.3 AND HAVE A SIMILAR PROBLEM

the truck does the same thing you dscribe

if i pop the hood and watch the motor i can actually see it

it actually feels like a miss

did the plugs and wires and some super duty injector cleaner

truck runs great and no loss in power , but it drives me crazy

a local mech said i could have a vacc leak and this would cause the injectors to over compensate??

i found a complete vortec intake w/ injectors and all on eBay

for 125.00 i can't go wrong

it also comes with TPS,AIC and 2 or 3 other sensors

if this is the fix i'll let y ou know

mech also said there could be a leak where the intake mates to the heads

soon as i get it on i'll post up

Todd

Lonewolf867 · August 29, 2003

I had a 2000 5.3 with the same problem. It would be running like a sewing machine and then it would just "bump" then continue smooth. Every couple seconds it would "bump" or miss. Not sure what the problem was or if it even was a problem. I did have a loss in gas mileage after about 40K on the motor. Maybe it was a vacum leak.

I now have an 03 duramax and I cannot , for the life of me, get the knocking out of it!