Question about 2004 Pontiac Grand Prix
I have had 2 new gas caps and am still getting the 455 code. I've also replaced the cat, O2 censors, plugs, and wires and am pulling a 420 code. What the hell? I have an 05 grand prix gtp and out of nowhere I've got this hesitation that is the worst at high speed acceleration and wide open throttle. Driving normally there isn't a problem....HELP
There are three things that can cause this that is unrelated to the cap, if the valve on the carbon canister is defective it would cause this it would also cause a vacuum leak making the car run lean so check the carbon canister check valve first. Next your EGR valve could be dirty or not functioning, depending on the model and engine size it may have two EGR valves one a mechanical and the other the digital EGR and it to may be dirty, if it's dirty it can be taken apart and cleaned with carburetor cleaner and clean the pintal. And lube the pintal valve. If you’re careful and not tear the gasket you can reuse it. If this does not seam to fix the problem then you have a vacuum leak or the device that pumps pressure into the gas tank may be defective.
Posted on Jun 27, 2009
P0420 is catalyst efficiency means that most like it needs a catalytic converter. P0455 most likely needs a EVAP vent solenoid both items are very common.
Posted on Jun 27, 2009
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Posted on Jan 02, 2017
Tips for a great answer:
Sep 12, 2014 | 1998 Chevrolet Astro
Jan 03, 2014 | Dodge Ram 1500 Cars & Trucks
Feb 05, 2013 | Nissan Altima Cars & Trucks
Sep 21, 2012 | 1999 Nissan Frontier
Mar 14, 2011 | 1999 Toyota Camry Solara
Jan 03, 2011 | 1998 GMC Envoy
Mar 03, 2010 | 2000 Pontiac Grand Prix
Jan 26, 2010 | 1996 Cadillac DeVille
Jun 30, 2009 | 1997 Chevrolet C1500
Mar 01, 2009 | 1997 GMC Jimmy
1,060 people viewed this question
Usually answered in minutes!
Step 2: Please assign your manual to a product: