1997 GMC Sierra Engine Light And Idle Surge

MY 1997 GMC SIERRA W/350 V8 HAS A DEAD CYLINDER ON #4. SPARK PLUG IS GOOD, WIRE IS GOOD DISTRIBUTOR CAP IS GOOD. WHAT ELSE COULD BE CAUSING THIS DEAD CYLINDER ? TRUCK HAS 117,000 WELL CARED FOR MILES !

ProTech:
Have you tried a compression test?

Not yet, but a compression test was next on my list.

I would do that for sure. You probably have a burned valve. Those engines were well known for burning valves which resulted in a dead cylinder.

2000 GMC 4.3 vortec v-6 Hard To Start

It usually starts on second try, misses and backfires, rough idle at start. Replaced the fuel pressure regulator, still runs the same and perhaps a little worse.

Does it act up more when the truck is hot or cold, or it does not matter?

It does not matter.

OK. Then you need to remove the distributor cap and look for water intrusion or green corrosion. This problem usually shows up more on wet damp days, but not always. If that looks OK, then you need to check fuel pressure. Even a few LBS. below 55 PSI, this engine will not start properly.

If i find the green corrosion, what would be the fix?

Just replace the distributor cap and rotor. The design was changed years back to eliminate the chance of water getting into it.

1998 GMC Pickup Has an RPM Surge

Happens about every five seconds while idling.

How much of a surge?

3,000 RPM.

What year GMC and what engine do you have?

1998 v6-262 4.3L.

Is the check engine light on?

No.

OK I would first check for vacuum leaks. Possibly something is wrong with the throttle body as well.

Thank you.

My GMC 05 Envoy won’t turn over it says service brakes, I checked the battery and the ignition sensor. Radio works need help.

Answer: The first thing to do is check all your fuses. Fuse panels are located under the hood on the drivers side and also under the rear drivers side seat.

If all fuses are good, then we need to check the battery. Just because the lights and radio are on does not mean there is enough voltage to get the truck to crank over. Try a jump start or get the battery tested.

If the battery is good, then you will need to check for power getting to the starter when trying to crank it over. You will need a test light. Put one end of it on a good ground and the probe end on the purple wire at the starter. The stater is on the drivers side, best viewed from inside the wheel well. Turn the key to CRANK and see if the test light comes on. If it does, you have a bad starter. If not, you have a wiring problem or even a bad CRANK relay in the underhood fuse box.