Question about 2005 Pontiac Grand Prix
I have two problems with my 05 Grand Prix. The more I dig online the more it seems the two are related. The first issue was a check engine light that gave me a mass evap leak code. Accompanied with that the check gas cap light was always on. I had the gas cap replaced and the code reset, worked great for a week or so and came back. Recently the car feels like it stalls just for a brief second. It has been getting worse and worse. The other day the car actually stalled and when I checked the engine codes I got a Cylinder 5 misfire code. I did some research and it appears the cadillac converter may be plugged causing back pressure to release into the weak cylinder eg the misfire and with the cc being pluged eg the evap error. How can I check to see if this is the cause? What can I do? How can I fix it?
Hello! There is a device called a purge valve; located in the back/right of the engine compartment next to the throttle body. The original fault was a "mass evap. leak code. Changing the gas cap was the correct, least expensive move. The purge valve is the likely culprit. If the catalytic converter was at fault a code indicating; Cat., or O2 sensors would have been set. If the valve can not open to purge the vapor pressure will give the faults you are seeing. Also if valve remains open auto will not run right anyway. Evaporator problems are unrelated to converter trouble. I suggest you replace the purge valve. There is also a vent valve located back by the gas tank; It is a part of this very complex system. Give that valve a good visual inspection (broken or worn wires/connectors or loose hose) before you purchase the purge valve.
Posted on Dec 10, 2009
Testimonial: "Déjà vu. They mechanic that solution 1 pointed to pretty much told me exactly the same thing. Thanks so much!"
Repalce the plug and switch the coil pack with another one . One thats on the car A GOOD muffler shop will let you know if your converter is bad. About 100 to 150.00 to replace. Get the universal one will work fine.
Posted on Dec 10, 2009
Testimonial: "Thanks! Your comment to go to a GOOD muffler shop pointed me in the right direction."
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Posted on Jan 02, 2017
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