I have a 97 monte carlo 3.1 that i just did a tune up on, changed the plugs, and wires. I also put oil treatment in it and gas treatment and new air filter, cleaned out the valve thats on the trottle body i forget the name of it, also checked the aic, All because the idle was bad when i was in gear, the lights would dim with the idle and i did all that and it still does the bad idle thing and now when i try and giving it gas it putters and wont go, the idles almost like go down when i gave it gas and almost died and i let it off and sat and made it back home. so it dosnt do that all the time it was the first time tonight. all help needed. thanks

 

You should change your fuel filter too as part of your tune up.

Sounds like your idle problem might be your catalytic converter.

 

In addition to the above listed things to do/check - I would also check the fuel pressure. Your pump might be going out.

 

How many miles does the car have on it? Is it possible the engine itself might be going bad? But like the other two suggested, get your cat cleaned/changed, new fuel filter, check your fuel injectors, check the fuel pump. And if all that fails, just buy a new Monte.

 

might be the coil packs but i would change the fuel filter first do to dirty fuel from preveuse fill ups if it didnt fix the problem coil packs or the relay for the fuel pump. they go just like a fues. if it didnt fix it fuel pump or the cat

 

Well the code brought up tranny slip, and misfire cyl. 3 so i dont think it would be a coil pack since just 1 cylinder is not working, there are 3 coil packs on my car and each one works 2 cylinders. There are also 110,000 miles on the car. The tranny seems to be fine i dont know why that code came up. Ill change my fuel filter tonight and do a pressure test on the car but does anyone know where the valve is to put the gauge on to see what the pressure is for my fuel pressure? thanks for the help.

 

catalytic convertor is clogged, IMO. Have a helper push on the gas pedal and see how much exhaust comes out. At 110K mi, if it's the original cat' you're luck you got that many miles on it. Mine went at 83K, and I've heard as early as in the 60K range.
The cat' screws up everything, including the tranny.

 

on your piticular model the coil packs are cheaper than mine because it is al one unit for me ie all one unit. i would change that puticular one to see if that is the problem. the fuel line valve should be hidden and a little hard to get to it should be under the intake manifold check the out skerts of it to try to find it it is easy to over look. it should be on the passengerside close to the fire wall but hidden by the intake manifold.

 

I did everything and could not find out what it was. brought it to a friend that works at a shop and told me it was the timing belt. The car now will not even drive. Well it drives but when you give it gas it totally tries dieing but when you release the gas pedal it goes back to good idle and then it will putter out and die. I was told the timing belt is on the other side of one of the pulleys which is by the serpintien belt. Its no good. thanks for the help

 

I'm voting for a cat problem too.