Car running like crap

[Milenko]

For some reason my car has been acting real funny lately.

I replaced all the spark plugs/wires, still has not fixed the problem.

It's idling roughly, and my passenger side exhaust pipe sounds crappy compared to my drivers side. Exhaust is fine, no leaks or anything. Passenger side sounds somewhat like a diesel engine from behind the car.

The car also doesn't seem to have as much power as it usually does. Air filter is clean too. All basic stuff has been replaced, including fuel filter.

Anything I should try?

 

[blumi00GT]

Could it misfiring on the passenger side? Due to a bad spark plug maybe? I think you double-checked yourself the correct firing order, dont you?

 

[Milenko]

Firing order is 100% correct. Problem was apparent before the spark plugs, but has gotten progressively worse.

What also happens is that if I let off the gas and let the car slow itself (5-speed), the exhaust sounds HORRIBLE, sputtering and sounding as if it is going to die. Never did that 2 months ago.

 

[Red2000GT]

2 other things to check. It could be a vaccuum leak. With the engine idling and hood open,stick your head close and listen for any "whistling" noises. Also your mass air meter could be messing up. Take it out and see if there's any nasty build up on the element. It's common to hear of problems after guys re-oil their K&N.(or K&N style)

 

[Milenko]

MAM/MAF is clean.

I've always had a vaccuum leak sound since I got the car. Didn't seem to affect anything.

 

[Milenko]

Anything else?

 

[TripleBlk]

Maybe you tagged a valve - try doing a compression test on the cylinder bank that's acting up.

 

[FordGT2K]

From what you described, i would guess 2 things before I would go through a compression test.

First of all what year is the car? Did you gap the plugs? I know these are stupid questions but it will only help you get to the bottom of this problem quicker. Does it have the Coil On Plug (COP) design, of 99 and up? If so I would start by making sure that all your coil packs are snug, lubricated, and fully connected. They have a tendancy to arc out but because there is no whire from a coil pack to the plug, it happens all down in the head. These are a real simple place to start because the car will still run if one is dying out on you and the remainder of the cylinders will carry the load. And often the OBDII will not detect the loss of spark to the plug because there is not a full failure. The low tech way to test and see if a COP has gone bad on you is when you have the rough idle, open the hood and unplug each cop, one at a time and listen to the motor. If you notice no difference than you have found the one that is dying. This just works to help you locate the problem, a little cheaper then bringing it to a tech and paying $60-$100 /hr. for them to locate a problem that the computer says does not exist.

Second, is it hard to keep the car running, and does it sound like your running a big cam in it. If so it may be the Idle Air Control valve (IAC) getting dirty and clogged with carbon. You can test that by removing it from the front of the intake plenum and cleaning it out with carb cleaner and reattaching it. This fix will only work for a little while but it is enough to get you by for a while. You will need to replace it.

Let me know if this was any help, I know i have had what sounds like similar problems and these are the ways that i went about fixing them.

 

[Milenko]

The car is a 96, and yes the gaps are perfect. I don't think the plugs are the problem, since I replaced them thinking that they were the cause of the problem. I was thinking maybe a clogged injector or something simple. We'll see, I'm going to take a close look this weekend.

 

[JLstang351]

Is it going away after 10 minutes or so? My car was doing this every now and then so I took it to auto zone so they could check my comp. I ended up replacing the fuel injecter pressure sensor,or somehting like that! Just take it up to auto zone and see if your computer shows any codes.

 

[Milenko]

Is it going away after 10 minutes or so? My car was doing this every now and then so I took it to auto zone so they could check my comp. I ended up replacing the fuel injecter pressure sensor,or somehting like that! Just take it up to auto zone and see if your computer shows any codes.

My CEL isn't on, should I still have them run a scan?