Question about 1994 Pontiac Firebird

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94 Firebird. Hesitates at 2K RPMs, surges at 3K. Low MPG, Rich.

This is a 3.4L V6, 5-speed, 167K miles. It started running rough, surging and hesitating. Mini vans were passing me on the right! I changed the plugs and wires. It ran great for about 2 weeks, then started to show the same symptoms as before the plugs and wires were changed in addition to smelling like it's running rich and plummeting fuel economy. I pulled the plugs out and 4 of the 6 were loose (couldn't find the torque wrench the first time), but all looked normal. Checked gap, all ok, torqued and reinstalled all plugs. Rd test, somewhat better, not much. No SES light on, went from about 20mpg to about 12. I'm thinking the oxygen sensors, but wanted another opinion before replacing things randomly. Also recently had new fuel filter, oil change, air filter. And if it is the oxygen sensors, how do you get them out? Even a deep well socket doesn't work. It needs a 3/4", there's not enough space to get a wrench to turn in there. Thank you!


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  • Anonymous Mar 15, 2009

    i have kinda the same problem check engine light come on oxygen sensor needed changed . and good luck with that it was a pain, you need to buy a special socket for the sensor its about 12 bucks then you need alot of swear words pb blaster and the right tools . even then my car ran awesome for two days after changing that now its back to the sluggish hessitation and ive changed everything you said you did ??


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Some other easy items to check. Remove and clean the MAF/MAP Sensor and the inlet to the thottle body with some brake cleaner/electronics cleaner. Also may want to try some Fuel Injector cleaner as well. The O2 Sensors usually require a special socket which you can buy at the local auto parts store, and you can also use a "Crowfoot" Wrench. Usually if the O2 Sensors are bad they will set off the Check Engine Light. Some other items to consider is a Rotor and Rotor Cap if you have a distributer instead of a coil.



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