1999 q45 running rough

[crittermitchm]

I have a 1999 infiniti q45. 153000 miles....running rough and backfires through the intake and resonator gets red hot, no power in drive....in park it idles rough and sometimes can acclerate.....only code i have is the P0300 random misfire....fuel pump, fuel filter replaced, and 2 oxygen sensors replaced on left side. no help.....can someone please help?...thank you.

[Lokim]

You have a clogged cat.

[BadQ45t]

He's probably right about that, but I would bet your spark plugs haven't been touched in a long time and the coil packs are shot too.

With that much going on and no good codes coming out of the car you're going to have cowboy up and find a good mechanic. these are cars are too complex for normal people to do serious troubleshooting. Best bet is to find a good friendly 3rd party mechanic that knows how to work on Infiniti products. The 99' is a pretty bullet proof platform when well taken care of.

Give us a bit more hisotry, how long you had the car, what has been done to it in the past (maintence wise)......also list your location and hopefully someone on the board can point you to a trusted shop.

[crittermitchm]

Left cat changed....exhaust aft of cat off car right now.......I'm in Orlando Fl.....Just bought the car with that problem from a friend who was broke...I doubt he did any maintenance.