spark plugs
 

my car skips when at a dead stop and you give it light acceleration. Once you get going it goes away. A friend of mine told me most likely build up on one of the spark plugs. its not reading a code for one but he told me it wont if it doesnt misfire enough.

even if this is not the issue its probably a good idea if i swap them anyway. So how is it doing them on these 3.8's? The fronts look easy as hell but...i cant even see the back ones.

- The stock plugs are good for about 100,000 (150,000 pushing it).
- Never use BOSCH plugs. AC Delco and NGK's recommended
- Change the plug wires while you are doing this.
- Changing the plugs is a piece of cake (some rock the engine forward, I have not had to do that).
- The metal heat shields on the plugs can present a problem gripping the boot of the plug wire to twist and pull off. I found making use of a good pair of vise grips, you can grab what little of the wire boot is sticking out and twist and pull.
- The back ones can be done by touch, no issues. Just feel the plug wire to where it ends. You can try getting them from underneath (I know you can see the boots), but I have always done up top.

Hope this helps.

Good stuff thanks man!

If you rock the engine forward, have someone step on the ebrake. That'll keep the engine tilted forwards without holding it.

I confirmed today i have a misfire, but its also reading the cat is below threshold. Can i safely assume its reading this because of the misfire?

On the plus side spraying the MAF sensor cleared that code.

This doesn't happen often But, I had the same problem. I had both a Crank sensor code and a cat code. Plugs were new, less than 1000 miles, Crank sensor was brand new. Found cylinder 2 and 5 were domesticated miss firing, the ECM was compensatimg by sending more gas causing the O2sensor code.
Turns out the middle coil pack, the one that goes to plugs 2 and 6, was going bad. I changed all three coil packs and the car is running great.
As I said, this is not common, as far as I know, But the symptoms are so similar, I thought I would offer this info to you. Good luck with your car!

P.S. Maybe I'm wrong But I thought the E brake was connected to the rear wheels? It is on my car! I no see how it would hold the motor in any position. Someone please enlighten me? :confused:

I don't recall the precise steps, but rocking the engine forward is working on stopping the car while the engine is in a certain geometry. If the ebrake is not pressed in, the chassis will move placing the engine back where it started.

If you are still on the factory cat, the 2000 and 2001 Monte's had a large batch of bad cats delivered to GM. You may simply have a failing cat (it creates exhaust air flow restrictions that can cause lost performance, mis-fire like symptom and sluggish "get up and go").
How did you come to the conclusion the cat is below threshold? Someone do a pressure test?

As JC Colon`mentioned, a failing coil pack is RARE and can cause a misfire. I had such a situation on a different car (94 Grand Am, used the same coils as the 3.8 non-sc Montes). I found by accident using my hand to apply pressure to the coil, I could make the problem come and go. And as JC Colon mentioned, the PCM will compensate by throwing more fuel at the mess (on a scan tool, that may be seen by a IPW, injector pulse width, being a higher number then normal).

Based on what you found, I would start with exploring the cat (get confirmation the cat is bad, if so, replace it), then hit the plugs and wires.

It's throwing a code for the cat saying below threshold l. The reason I believe it's linked to the misfire is both codes popped on at the same time.