Engine rough, what is wrong with this thing?

[Skye]

Trying to diagnose this problem I put in a new ignition and O2 sensor before the cat. Nothing helped.

Today I put back in the old ignition, disconnected the battery, let it sit for a bit. I started it up, it sputtered once but the engine light was off, it seemed to smooth out. I took it for a spin down the road. It seemed to get up to temperature quicker than I expected it would, but it never went past horizontal. Ran like a top, not a single problem.

I hopped back in to take a longer ride, it seemed to want to start sputtering when I turned on the heat (it's cold out) but I figured I'd go anyhow and see how it acted. I took it to Blockbuster, no problems. I drove it to the mall, no problems. I got back out of the store, cranked it up, it's running like total crap again. Engine still throwing no codes.

I've got to limp it home so I start out of the parking lot and it's bucking like it's running on 3 cylinders. I start down a road and it's backfiring under the hood. I stop at a light and it's rhythmically bucking. Lights green, start moving again, still running like total crap and backfiring like crazy.

I made it home, still not the first light on the dash.

More new plug wires?

Thoughts? (2004, non-turbo, auto, 75K)

[CREWZIN]

Skye,

Is this different than what we were talking about on the fan thread? This problem almost sounds like you got hold of some bad gas but ignition problems could cause the same type of bucking. Sounds like yo need to get hold of a mechanic with an OBDII scanner and narrow it down.

[Skye]

She does have a full tank of gas. If she did get some bad gas, is there anything over the counter worth adding?

The only thing that throws me is that it was running fine, turned the car off, ran like crap. Just can't pin it down...

[CREWZIN]

We can only guess, you need professional tools. Chevron Techron is one of the best gas treatments on the market.

[Skye]

I'll drop in some of that. I've also been advised to pull the plugs one at at time to see if I can narrow the problem down to one plug. Likewise with the injectors. Also try to clean the MAF.

I'll keep the thread updated, someone else may be going through this at some point, lol

[TurboMoparDave]

When running the heat was it in the defrost or floor/defrost setting? Both of those run the A/C compressor so this may be related to the fan issue you described in the other thread.

[Skye]

O reeeeeeeally? I'm not sure, I didnt think to check that, but I will!

[crusierdad76]

the odd thing is that bad gas will cause a backfire and THAT should throw a Cylinder misfire code??????