engine cuttin out?

**1998burbon** · 08-06-2009, 10:52 PM

Hello all, I have a 98 GMC SLT Suburban 5.7/4L60E(All factory) with 180K miles, and it was fully tuned up at 150K which included plugs/wires/cap/fuel filter. 3 days ago i noticed that when i started up hills while on a highway. it seemed to chug as i crested hills.

Yesterday, i noticed it more and even on cruise control, it would still chug as it climbed even the slightest hill. Today, it was real bad and is starting to cut out alot when u accelerate. But once u get to your desired speed, it runs smooth, so it just gets bad when under a load......It seems like it could be electrical, but i don't know....

I guess my question is, where do you think i should start looking? I used to be a parts hanger, but im no good at diagnosing......And just checking to see if any of u all ever had these symptoms before......

**1998burbon** · 08-06-2009, 11:18 PM

Forgot to mention that so far, the check engine light has not come on and all gauges are running normal.....

**tattooed4life** · 08-07-2009, 12:20 AM

Have you checked/replaced the fuel filter? Check your fuel pressure, you could have a clogged filter. Under load it may be starving for fuel, while at crusing speeds it's still clear enough to just "sip" fuel.

**2ToNe04** · 08-07-2009, 02:29 AM

what did you tune it with?

**1998burbon** · 08-07-2009, 04:22 AM

Well, it was done at a mechanic shop on the tune-up, so i don't really know.........

The fuel filter could be clogged i guess, i will change it myself after i get off work today. It probably needs a new one anyway since it is 30K miles old. Atleast that is fairly cheap.....I'll let u know if it helped any. Thanx

**mrfixdit** · 08-07-2009, 05:13 AM

I once had a problem exactly like that with my '94 Jimmy. It seems a mouse was testing my plug wires to see if they were edible. Being unable to chew them up he just managed to leave a few very small pinholes in them that would short to the manifold when under load. Good luck!

**Jimmiee** · 08-07-2009, 08:15 AM

Cruise by Auto Zone and check for codes. The computer will log misfire information which can point to the problem. I know the check engine light has not come on, yet.

**heavy chevy** · 08-07-2009, 12:39 PM

if it is not your fuel filter it will be your cats. 9 out of 10 times on older vehicles this will be the problem when it is doing that. you should change your fuel filter every 12500 miles any way it is only like 15 bucks.

**1998burbon** · 08-08-2009, 12:58 PM

Well, i cleaned out the egr valve and changed the fuel filter, and no change.......I sprayed down the engine with water, to see if i could get it to miss at idle, but no luck there......It still seems like it would be electrical....The more i push the gas, the more it chuggs. Especially on the highway......

**Jimmiee** · 08-08-2009, 02:21 PM

Originally Posted by 1998burbon

Well, i cleaned out the egr valve and changed the fuel filter, and no change.......I sprayed down the engine with water, to see if i could get it to miss at idle, but no luck there......It still seems like it would be electrical....The more i push the gas, the more it chuggs. Especially on the highway......

If you have an electrical problem chances are real good that your computer would see it and set a trouble code. Have you chacked for codes yet??