[robbynoble01]

Mustang starts missing on cylinders 4 and five, took out the spark plugs and replaced them, checked the wires and the coil pack and all of that is good, could a blown headgasket do this???

 

[heavy metal]

Welcome to the site!!

 

[B.Cooper]

What wires did you check? I would still try some new coil packs that is almost always the problem. A good way to make sure is to take those coil packs and switch them with another pack and see if that cylinder shows bad. Best of luck.

 

[Bigrob747]

Switch 2 coil packs and 2 spark plugs from the other side of the engine. Clear Code and wait for codes to come back. Or you could replace those sparks just for good measure. Run some seafoam through a vaccuum line and make sure all your electrical connections dealing with the ignition system are clean on the inside and dry. Also make sure your coil connectors snap all the way down on the coil pack. I had this problem with a misfire.

 

[robbynoble01]

Thanks for the help guys, but I tried a lot of different things and I'm pretty sure that its fuel injectors but I rented a fuel pressure tester and it said that I had 0 fuel pressure, and I'm pretty sure I had it on the Schrader valve, it was the only open port on the fuel rail, I still have to check the compression but this is really getting tough to diagnose

 

[B.Cooper]

If you had it on the schrader valve and had zero fuel pressure you won't notice a miss because your car won't be running. Also if you have no fuel pressure at the schrader valve it would most likely be a bad fuel pump not injectors. Best of luck.

 

[B.Cooper]

Silly question but when you checked your fuel pressure did you have your key turned on to the accessories position?

 

[robbynoble01]

Yea and the car totally runs, maybe its just a bad checker, I narrowed it from O'Reillys

 

[robbynoble01]

Barowed

 

[robbynoble01]

Also rev'ed it up max twice but the dial didn't change

 

[B.Cooper]

Yeah it doesn't sound like a fuel issue. I would bet that if you changed your coils with ones that are working now your problem will change to the new cylinders.

 

[robbynoble01]

Yea well I've had a good friend of mine help me out a lot on it but he's a Toyota mechanic, and through all the stress and aggravation he is still scratching his head so I think I'm just gonna have a certified mechanic diagnose it then I will probably trytofix it myself

 

[stevew01]

Well, to come in and offer some help to this lets start with eliminating the obvious. You asked if it could be a head gasket. Yes and no. Yes it could be a head gasket as that will cause a misfire on a cylinder if you are low on compression. No I highly doubt your 01 GT has a head gasket issue since the passenger side of the engine bay is straight in order cylinders from front to back are 1,2,3,4. Drivers side are 5,6,7,8. So if it were in a fact a head gasket you would need both sides as your codes are for the rear on one bank and front on another bank. When you pulled the plugs out did they look bad? Was they soaked with gas? If this car is stock buy yourself 8 new spark plugs (Motorcraft if it is stock) a nice good copper plug will work if it is modded. Also pick up 2 new coils and change out the right side rear coil and drivers side front coil and repost your findings. I bet cylinders 4 and 5 arent missing anymore after that. Let us know.

 

[robbynoble01]

Alright guys thanks for the help I finally got it it was the damned coil pack, I was just gonna give in and take it to a mechanic but when I looked up how much a coil pack would be I was gonna but it test it clean it and try to return it, but it worked and I was super psyched best momentofmy year. Thanks for the help again and if I ever have another bog problem I am definitely comping back