Kdids82

I have a 1999 camaro with a 3.8 3800 series V6 and a 5 speed transmission attached to it. I have recently developed a problem and noticed when it gets started up on a cold motor, like in the mornings, it will sit there and the entire engine will shutter back and forth more than it would normally. When I first noticed it, I thought it was just because of the cold motor but it wasn't that. I will put my foot into it, it will sound like a spark plug went out and its only running on 5 cylinders. But once it warms up, it'll fix itself and get all the regular power. The shifter *** inside the car will also vibrate more that it would normally too. I dumped some heet cleaner into the tank and that didn't work. So what could it be?

MMWS6

I'd be checking for vac leaks first. Any connection from MAF to O2 sensor, especially intake manifold and PCV system. No codes I take it?

Kdids82

it's throwin the service engine soon code and thats about it

87silverbullet

iTrader: (11)

Go get that code scanned at Autozone for free and let us know what it is. Sounds to me like its going to be P0300 for misfire.

Kdids82

So if it's a misfire code would I have to change the plugs? Or what would need replaced

87silverbullet

iTrader: (11)

No. That's a parts changer attitude. You will spend all kinds of money and still won't fix the problem. You would want to diagnose this correctly and not just throw parts at it.

First you need to find out what that code is. Second, if it is misfire then we need to see what cylinder it is. It could be an injector that's clogged, spark plugged cracked or coil pack could be going bad.

Kdids82

okay thanks i will get it checked out

Kdids82

I went and got the code read and it came up sayin both o2 sensors are bad, random misfire, EGR valve is bad and stuck open, and plugs an wires needin replaced.

Kdids82

which one do you guys recommend i start with?

sreve

iTrader: (3)

No it did not! Some lop eared kid at AZ may have told you that
(I wonder if they make commission) but each fault has a code.
You are going to go down the road 87silverbullet warned of.

87silverbullet

iTrader: (11)

I would of liked for you to have gotten the codes for each one because there are a bunch of different codes for o2 sensors and we need to find the exact code.

As for the cold start shuddering and random misfire, it does sound like to be your EGR valve being stuck open. An egr valve redirects exhaust gas help warm the chamber up to reduce emmisions but when its stuck wide open it will produce the condition that you have now.

I have had the same problem with all of the 4.3 liter vortec engines of back in the same era of your car. People would use junk corner store gas and it would create a carbon build up and make the EGR get stuck open. I would take it off and crank the engine to let it blow out the chunks of carbon and clean off the egr the best I could. If all that didn't work, I would just replace the EGR. The o2 sensor code might be with this issue too with the ehaust gas being recirculated It might be showing a rich condition from partially burnt gasses and throwing a CEL.

Check your EGR first and go from there.