Tahoe started to run weird!

[hertahoe]

2005 Tahoe LT with 136k 5.3l. It has never done this and has always ran smoothly! So last night I took her truck to the store about 10 minutes away. All was going well until I got into parking lot. Was stopping at stop sign and it started a slight surging effect. Put it in neutral and could still feel something isn't right. Put it back into D and hit a spot. Put it in and out of D a couple of times and same thing. Went and got a few items and looked underneath and no fluid leaking. Runs fairly smooth and no other sounds than it running a bit rough. **** it, lets go. Took off slowly and way down on power and seemed like it was missing, but no loud sounds, like backfiring. Get to first light, put it in neutral and looked at gauges and all seemed good expect the gas mileage readout. When I stated it said range was about 167milles. Now it stated 75 and started to go back above 100. I noticed a small bit of steam/smoke coming from front right of hood. But very small. Took off slowly and was surging, but not like a bucking bronco. Got it back the 3 miles to driveway. Opened up hood and no leaks visible (nor this morning) and idling decently and no signs of smoke or steam. This is baffling to me.

Edit: The check engine (yellow) would flash on and off. Not constantly flashing. I will admit, I don't have a OBD reader. So which one should I get?

 

[corvette744]

Maybe start by going to autozone for a free code reading-see what cha got.

 

[Cbncanada]

A little water in the fuel perhaps.

 

[SnowDrifter]

If you start it up now, after everything is cool, how's it run?

 

[hertahoe]

A little water in the fuel perhaps.

Could be, but it's garaged and use Costco gas. Had gone on a trip to her mother's that is 125 each way and drove like it always has. I could put some seafoam in.

 

[hertahoe]

If you start it up now, after everything is cool, how's it run?

A little off. Just ran to Autozone and picked up a reader. It has P0301 code. Could be plugs, wires, coil pack, injectors or vacuum leak. So the chase begins.

 

[hertahoe]

Maybe start by going to autozone for a free code reading-see what cha got.

Just went to Autozone and picked up a reader. Code P0301

 

[gooffeyguy]

That code is cylinder 1 misfire.

A vacuum leak would generate random cylinder misfires

I'd clear the code and see if it comes back the same after driving it. If it does, check and make sure spark plug and wire is tight, and maybe swap coil with another cylinder and clear code again and see if same one comes back of if it changed to the other cylinder you put the coil on.

 

[Fless]

If your scan tool can count or graph the misfires by cylinder number, that would give you more insight into which one might be misfiring. Don't lend too much credence to the cylinder number by just the code.

 

[Scottydoggs]

flashing cel generally means one of two things. you need a tune up real bad, or one or both cats are clogged up solid.