Rough idle, no power

[brianharp]

My 99 grand prix gt is idleing very rough and when i try and drive it the ses light flashes and it has no power. No water in the oil that i can see or oil in the antifreeze. Replaced the plug wires but no help. Any suggestions?

[Scottydoggs]

clogged cat would be my guess. how high are your miles?

[brianharp]

I have 235,000 on it but the engine has been swapped. A buddy of mine mentioned it could be a cooling system sensor throwing it off too. The coil pack has been replaced as well as the MAF sensor, EGR sensor, fuel pump, spark plug wires, etc. When I rev it up in park it smells really strongly of gas. I have had problems with it dieing periodically when taking off from a stop, but it has been doing that for the entire time that I have owned it

[Fivefingerdeathpunch]

I'd unscrew the upper o2 sensor, and give a quick spin.

Yes it will sound like a tractor, but if it allows the exhaust gases to escape faster it may drive better and not stumble/misfire on you. Then you'll know if you have a plugged exhaust or not.

You could also heat gun the exhaust or do this at night, if the cat glows red you know you have a issue.

[Scottydoggs]

so you have 235,000 on that cat. id bet money on the cat.

at night, drive it some what hard, try not to make the cel flash, cause thats real bad, then stop in a dark area and see if its glowing.

[brianharp]

where is the upper o2 sensor located?

[Scottydoggs]

its that thing thats blocking that spark plug in the rear manifold, you need a 7/8 th's o2 socket to remove it.

[brianharp]

Ok thanks. I will try that. I would take it out and drive it but the ses light flashes as soon as you try to drive it.

[Scottydoggs]

does the engine sound like a vacuum with a full bag when you floor it? like it wants to suck air but just cant? if so the cats clogged up for sure. some times a few good shots with a hammer to the cat will unclog it temporally. if you hear stuff rattle inside the cat when you hit it lightly its all busted up inside for sure.

[brianharp]

Took out the o2 sensor and still is running bad. Ses light flashes when driving but not when just idleing. Any more suggestions? Could it just be a bad set of plugs?

[Xorbex]

Have access to a scanner to check codes? I had a leak on my intake that acted like that.

[brianharp]

I will go to auto zone tomorrow and have them scan it.

[ThePhoenix98]

Just had the same issues on my 00 GT. threw a p0134 for the o2 sensor and
p0303 misfire on cyl 3. replaced the o2, icm, and 3/6 coil and she runs good
as new as of this morning.

[99GT2dr]

You replaced the plug wires, but not the plugs? With the strong gas smell, keep an eye on your oil, if it gets contaminated with fuel, you'll wipe your bearings out in short order.

[bobc455]

Did you put the wires on the correct plugs?

[brianharp]

I replaced the plugs also and yes i put the wires on the right plugs. When i drove it to o reilly's to get the codes checked it gave me the same ones as the person above. When i pulled back into my house the water pump went out sofor now it will just be parked until i can figure something out.