Hesitation in mornings

gmc
1500

#1

For the past 2 mornings, my 97 GMC Sierra pick-up has had a slight hesitation when accelerating. After it runs a while, there’s no problem. In the afternoons, it doesn’t do this. It is at the shop now & of course, if didn’t do it while they had it, so they are still checking for problems. Any ideas? Thanks


#2

I assume no check engine light?
Has the manual recommended maintenance (filters, plugs etc.) been done? That’s where to start.

From there put a bottle of Chevron or Sea Foam in the gas tank.
Get the ignition system checked out.
Check the fuel pressure.
Get a compression test.
Get the head gaskets tested.

Hopefully it will be fixed before you reach the bottom of the list.


#3

There’s something wrong in the cold start system, like the coolant temperature sensor or the Idle Air Control. You may need to visit a dealer or other mechanic who is familiar with these trucks.


#4

Thanks, they replaced the oxygen sensor today. We’ll see in the morning if that works. It was fine on the way home.


#5

Has it been damp in the mornings? How old are those spark plug wires?