1998 Pontiac Grand Am sputter and no power problem when war

1998 PONTIAC GRAND AM
180,000 MILES • 6 CYL • FWD • AUTOMATIC
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CALMO1986
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  • 2 POSTS
Well for a few weeks now when im driving anytime i get to a steady speed and hold the rpms at 1500 they will jump up and down sputtering making the car kinda buck. well i started troubleshooting myself and i replaced the plugs and wires, there gapped right plugs in the right spot but i took it out, starting out and up throught the lower rpms it instantly had no power, it bucked, and it was like i had to force it to go but i had alot of power if i floored it and went fast. And all that was while it was hot outside. i drove for about 10 miles to base. And when i stopped i checked to see if a wire fell off and they didnt but when i leaned over the engine it was rly hot and smelled like something was burning. I checked with the shop on base and they said it sounded like the catalytic converter cus it wasnt throwing any codes, they told me to have it checked at a muffler shop but i wanted to ask u guys first. and then i went to work this morning and it was cold, probably 50s and it didnt do it at all. Im stumped and im trying to narrow it down before i spend alot of money.
Sep 4, 2009 at 12:14 PM
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MMPRINCE4000
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  • 8,548 POSTS
It is very possible that the convertor is clogged or partially clogged.

If the convertor is bolted on, unbolt and visually inspect the material inside. Should look like a honeycomb. If black,melted,cracked it is bad.

If convertor is not bolted on, perform a backpressure test on it.
Sep 5, 2009 at 8:33 AM