: Re: 2000+ Northstar Plenum Replacement steps



Grady1
10-11-12, 09:40 AM
I have an '03 Aurora with 135,000 miles on it. On high idle the car will run fine but once it comes off of high idle it starts to miss, sputtering out the tail pipes. I sprayed a ton of carb cleaner around the plenum but didn't hear any change in the RPM's. Is most of people finding the tear in the plenum is on the bottom? I don't have all the codes as I've had a garage put it on a scope. I know one is: misfire on cylinders. One thing that baffles me is once the system is reset, the light goes out, the car runs great for 15-20 miles, then once the light comes back on it starts to act up. At highway speed it runs great. Does this sound like a plenum issue? Thanks. Grady

sts 03
10-12-12, 12:40 PM
I'm going through something similar as you but I don't have any codes.I spray the plenum but didn't notice any change really in rpm,I heard you need to flex the plenum when spraying to open the rip up if there is one.i'm changing mine this weekend I hope this fixes it.search plenum on this site or go to tech tips there is a thread with steps on to change the plenum.

Grady1
10-12-12, 02:19 PM
sts, I bought one of the OBD2 scan tools. I've been getting the same code as the guys at the garage were getting P0300, which is random misfire. Here is a good write-up on it.http://www.random-misfire.com/. I'll be tackling mine next week, as I ordered the parts off Rock Auto. Good luck with your's. Grady

sts 03
10-12-12, 02:54 PM
I'm assuming your engine light is on.what baffles me is my car will stumble on acceleration have random high/low idle sometimes car wants to stall When coming to stop ,rpm bounce up and down when braking sometimes but no codes.you know you can pull the codes on your dash, there is a sticky where the threads are on how to pull codes using your onboard code reader.