1998 Pontiac Grand Am Car Problems

1998 PONTIAC GRAND AM
128,000 MILES • 4 CYL • 2WD • MANUAL
Avatar
DRB3BOY_21
  • MEMBER
  • 1 POST
My Pontiac grand am sometimes will start and run fine. Then sometimes it will start and run like crap absolutely no power and stalls out if you let go of the gas. Then sometimes it wont start at all if you dont press the gas medal awhile it is trying to start.
Thats pretty much the basic. Ive checked a few things like plugs and wires and replaced. Still the same problems.

I also have a engine code P0420. Catalyst Efficiency Below threshold bank 1. Is that something to do with the catalytic convertic. If so does that mean it needs to be replaced. Just want to make sure before I do. Thanks
Dec 12, 2007 at 1:56 PM
Advertisement
Avatar
RASMATAZ
  • CAR REPAIR CONTRIBUTOR
  • 75,992 POSTS
P0420 in most cases, is an emissions issue, not a performance issue that affects the way the engine runs.

You might want to have the exhaust sniffed with a gas analyzer before and after the converter to confirm that the gases are being scrubbed thru the exhaust system. If not could be the converter or an oxygen sensor/s problem.

Also have the coolant temperature and throttle position sensors and idle air control valve check.
Dec 12, 2007 at 2:15 PM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.