94 NA 347 Cobra - Stopped Running

**94Cobra** · 06-20-2010, 12:40 PM

The car was running awesome on Friday as I drove it 40 miles to work. Started it Saturday morning and it idled fine for 3 minutes while I lubricated my belt tensioner since it was squeaking. Then, it began to run rough and stumble while idling. As time went on, it began to run rougher and miss even worse. I noticed that a loud air rushing sound was coming from the air filter. Giving it some rpms helped but the stumble was still there. Eventually, I had to shut her down. I let it sit until Sunday morning and now it won't start at all. It it trying to start so I don't think it is a spark issue. I am beginning to suspect that someone dumped sugar or a contaminant in my fuel tank since I don't have a locking gas cap. I am planning to drain the fuel tank. Does anyone have any other suggestions or ideas? Does this sound like bad fuel? I checked the Intake Air Temp and Coolant Temp sensors and the resistance was good on them. Thanks in advance for any help.

**somethingclever** · 06-20-2010, 02:53 PM

Before dropping the tank, why not check for fuel at the injectors first?

You need three things:

spark
fuel
compression

I would check the first two before anything.....

**349Stroker** · 06-20-2010, 04:27 PM

Originally Posted by somethingclever

Before dropping the tank, why not check for fuel at the injectors first?

You need three things:

spark
fuel
compression

I would check the first two before anything.....

x2...do you have a fuel press gauge and i know this is a stupid ? but is there gas in it?

**94Cobra** · 06-20-2010, 05:00 PM

There is fuel in it. I have an aftermarket fuel pressure regulator and a fuel pressure gauge. The fuel press. gauge is stuck on 15psi whether I crank it or not. If memory serves, the fuel pressure gauge used to drop to zero before when I would shut it off. I am thinking about cracking open the fuel system somehow to see if that helps at all. Thanks for your help so far.

**White5.0** · 06-20-2010, 09:42 PM

pull and check all of your spark plugs

**89 vert** · 06-20-2010, 10:09 PM

Originally Posted by White5.0

pull and check all of your spark plugs

YES do this first!! I just found out the hard way. I was chasing a miss for 2 weeks. I wasted time and money because i did'nt pull all of the plugs, just a few. 2 were bad.

**349Stroker** · 06-21-2010, 01:06 AM

Originally Posted by 94Cobra

There is fuel in it. I have an aftermarket fuel pressure regulator and a fuel pressure gauge. The fuel press. gauge is stuck on 15psi whether I crank it or not. If memory serves, the fuel pressure gauge used to drop to zero before when I would shut it off. I am thinking about cracking open the fuel system somehow to see if that helps at all. Thanks for your help so far.

15 psi isn't gonna start that car

**94Cobra** · 06-22-2010, 11:22 AM

Originally Posted by 349Stroker

15 psi isn't gonna start that car

Would a bad fuel pressure regulator cause the low fuel pressure issue? That seems like a stupid question, but has anyone ever seen one of these fail? The one I have is an adjustable Aeromotive pressure regulator. The fuel pump is less than 4 years old, which leads me to think it isn't the pump.

**349Stroker** · 06-22-2010, 11:25 AM

could be pump...could be regulator...could be a voltage problem

**TJH64** · 06-22-2010, 12:08 PM

Check the fuel filter...you may have a restriction, possible some debris, rust, etc got jambed.

**wick** · 06-22-2010, 02:35 PM

Pull the vac line off the regulator and see if it smells like gas. If it does then you have a bad regulator. For some odd reason though, you are the fourth car I know in the last month that is dropping fuel pressure.

**94Cobra** · 06-25-2010, 12:21 PM

I fixed the problem by installing a new fuel filter. Thanks to all who responded. The old filter was only 3 years old, but I do put Sta-Bil in the tank and store the car without starting it all winter. This year, I think I will switch to SeaFoam for a fuel stabilizer over the winter. Or, I might just do without any stabilizer.

Originally Posted by wick

Pull the vac line off the regulator and see if it smells like gas. If it does then you have a bad regulator. For some odd reason though, you are the fourth car I know in the last month that is dropping fuel pressure.

**Martin0660** · 06-25-2010, 03:14 PM

Originally Posted by 94Cobra

put Sta-Bil in the tank

I'm not a fan of that stuff. Sure not a car, but the only time I used it in my power equipement (snow blower, mlawn mower, etc), I fought with gel in everything. It will never be in anything of mine again.

**PaxtonShelby** · 07-04-2010, 12:56 AM

Glad to hear it was just the fuel filter - cheap and quick fix! I've never used any type of fuel stabilizer - I just run premium fuel all the time and keep the tank over 1/2 full when I store the car from October thru ....uh....JUNE ( this year ). Every year it starts right up. ( of course by saying that I probably jinxed myself... ) I don't really whoop on it too much until that initial 1/2 tank is burned up - but in my car that doesn't take long, even with "normal" driving. :D

**94Cobra** · 07-04-2010, 02:11 PM

Yeah Ron - no more Sta-bil for me. My KR is idling like crap and I'll bet it is due to the StaBil I used in it. I had to have a flatbed tow my Cobra from the bottom of my driveway 15 feet into my garage. The lady at AAA thought I was nuts when I told her I needed a tow 15 feet. The grade on my driveway was slightly too steep to push it or jack up the car and work on it safely. After I got it towed into my garage, I had it running in 45 minutes.

The car is up at Joe's to fix the leaky axle seal again. He loves to see my car at his place because he gets to take it for a test drive!

**PaxtonShelby** · 07-04-2010, 06:52 PM

Sorry to hear the KR is giving you some fits. I bet you're right that it is because of the Sta-bil. That car had been running perfectly the last few times I saw you. What's the best way to cure that - maybe a 1/2 tank of 100+ fuel and some hard miles on 279???

Look at it this way... at least 2/3 of the toys are now problem-free!