Help with a rough running pony :(

ThePope · Sep 26, 2007

Hey everyone. My 98 GT has been running really bad for 2 days and I wanted to post to get some ideas from everyone. Just to give everyone an idea about what my stang goes through Monday through Friday. I work as a utility contractor testing street poles for New York State Electric & Gas. So for 11 hours a day, my car stays running for about 98% of that time. Anyway, when I came back from testing a pole, I heard the engine running rough like it wasn't running on all the cylinders. So I pulled each wire off the coil one by one to see if it changes. Turns out, cylinder number 5 wasn't getting spark. So I replaced both coil packs with brand new MSD Coil Packs. Part number 8241. So I changed them out yesterday and the car run great after that. So this morning on the way to work I noticed it wasn't running right again. It idled rough, exhaust smelled like gas, car drove like ass. Through out the day it got worse. So at this point, I am thinking that the plugs are maybe failed out. I figure since I drove the car on 7 cylinders for about 4 hours after the problem started up until the time I put on the new coil packs. As for engine mods, it has only a cold air intake. It has a up to date intake manifold which was installed at around 95,800 miles. Then at about 96,000 I put on new plugs, wires, fuel filter, and PCV Valve. All motorcraft parts. Like I said, I think it might be the plugs needing replacement but I wanted to see what everyone thinks before I make any moves. Thanks everyone.

Jrgunn5150 · Sep 26, 2007

I would try plug's first. Now that updated intake, is it an NPI with an alloy crossover, or a PI?

reivaxtorres · Sep 26, 2007

check the plugs to see how they look, and make sure that the intake manifold hasnt started leaking (even the revised ones can leak, but thankfully they just need a few bolts tightened) and managed to get coolant into the spark plug hole. how many miles are on the car now? it might be time for some new plugs and wires.

when you say the car smells like gas, do you mean it smells like you're at a gas station, or it smells like the car is running really rich? when my o2 sensors crapped out like 3k miles ago, my car ran so rich it hurt my eyes to have the windows down, and i have cats on the car! my car also ran like crap when the o2 sensors died. installed new ones (motorcraft) and the problem went away.

i would:
1) check plugs. if they look fouled up, replace them.
2) depending on miles, check the plug wires and clean up the terminals, or just replace them.
3) check the MAF sensor. if its dirty from the filter oil, its not going to be reading the correct amount of incoming air and it will adjust the fuel delivery accordingly.
4) if you can, see if you can get the o2 sensors checked. most mechanic shops should have an advanced scanner that they will hook up to the computer and be able to see what the o2 sensors are reading, and see if they are working properly. stick to either FoMoCo or Motorcraft sensors.

scarface · Sep 26, 2007

It sounds like fowled plugs to me.

ThePope · Sep 26, 2007

Jrgunn5150 said:
I would try plug's first. Now that updated intake, is it an NPI with an alloy crossover, or a PI?

I have a stock 98 GT engine with the updated intake.

Jrgunn5150 · Sep 26, 2007

Ok, if it was a PI intake I was going to suggest a water leak might also be a cause. But I would get new plug's anyway, have they ever been replaced?

ThePope · Sep 26, 2007

reivaxtorres said:
check the plugs to see how they look, and make sure that the intake manifold hasnt started leaking (even the revised ones can leak, but thankfully they just need a few bolts tightened) and managed to get coolant into the spark plug hole. how many miles are on the car now? it might be time for some new plugs and wires.

when you say the car smells like gas, do you mean it smells like you're at a gas station, or it smells like the car is running really rich? when my o2 sensors crapped out like 3k miles ago, my car ran so rich it hurt my eyes to have the windows down, and i have cats on the car! my car also ran like crap when the o2 sensors died. installed new ones (motorcraft) and the problem went away.

i would:
1) check plugs. if they look fouled up, replace them.
2) depending on miles, check the plug wires and clean up the terminals, or just replace them.
3) check the MAF sensor. if its dirty from the filter oil, its not going to be reading the correct amount of incoming air and it will adjust the fuel delivery accordingly.
4) if you can, see if you can get the o2 sensors checked. most mechanic shops should have an advanced scanner that they will hook up to the computer and be able to see what the o2 sensors are reading, and see if they are working properly. stick to either FoMoCo or Motorcraft sensors.

When I say it smells like gas, it smells like the gas isnt burning and just going out the pipe. Like a typical missfire.

ThePope · Sep 26, 2007

Jrgunn5150 said:
Ok, if it was a PI intake I was going to suggest a water leak might also be a cause. But I would get new plug's anyway, have they ever been replaced?

At 96K, I replaced everthing. Plugs, wires, pcv, fuel filter. The car now has 108,000

Jrgunn5150 · Sep 26, 2007

Then I would just locate the fouled one and replace it, if you used platinum's. That should save you some coin.

ThePope · Sep 27, 2007

OK here is an update. I changed all the plugs and the car is still running the same. So I hooked up my diablo tunner to see if there are any codes. No codes. So I then looked at the live data while it was running, I noticed the FRP PSI was reading 0% So now the car is running the same but now white smoke is comming out of the tailpipes.

Suthrn98 · Sep 27, 2007

white smoke usually means burning water. I had this same problem on my wifes dodge ram and it turned out to be a cracked head..

Jrgunn5150 · Sep 27, 2007

I would look at your intake then, since it was also replaced. Mine was leaking water from the heater hose connection in the back.

reivaxtorres · Sep 27, 2007

Suthrn98 said:
white smoke usually means burning water. I had this same problem on my wifes dodge ram and it turned out to be a cracked head..

it could also mean a blown head gasket. pure white smoke means coolant/water burning, white smoke with a blue tint means that its buring oil. if its burning coolant, it might mean anything from a cracked head gasket to a cracked intake gasket. do you happen to know if you have the Ford OE replacement NPI manifold (revised) or the Dorman replacement NPI manifold?

ThePope · Sep 27, 2007

Well I fixed my running issue. For shits a giggles, I bought new coil packs. Put them on. Start it up. Ran the same. Except I hear a arcing sound. Turns out, cylinder 7 spark plug wire is arcing. So I ordered some new ford racing 9mm wires. Thanks everyone who helped me out.