Ok, here are the symptoms. When I load the car and try to get it to make power, the car stumbles as if traction control just kicked on. It's like the spark is turned off or the fuel is completely cut off. If you don't pull your foot out of it quick enough the car dies. The car cruises around like normal when you don't load it very much. I can drive it around the neighborhood and down the interstate 100 miles (I did this morning) with no problems. When I try to load it the car stumbles and occasionally the engine completely dies. I can be cruising at 70mph on the interstate in 5th and start to press the gas and at a certain point the car starts to either miss or just completely fall on its face. Not like detonation, like the fuel or spark is cut off. :shrug: Twice today I was just cruising down the road (no significant load) driving to my cousin's garage when it started stumbling and died. Both times it took a few minutes to get the car started back up. The car isn't showing a check engine light and the traction control or other lights on the dash aren't being displayed when this occurs.
The history of changes to the car up to the time this happened:
1.) I put gas in at a mom and pop BP/Amoco 25 miles before this started (I have been using this station for over a year with no problems before). I have since put in new chevron gas, changed the fuel filter and added gas treatment and driven the car several miles, problem still the same. I have been changing the fuel filter every 6,000-10,000 miles.
2.) I installed brisk 15 series plugs like the ones many 03/04 cobra owners are running (GOR LGS 15) about one week ago. I have put around 800 miles on the car since then. Plugs smoothed out the idle and low rpm surging pretty well. I changed the plugs to some new NGK TR6s to try and elimnate the brisks from the equation for now.
At first I thought it might be the fuel rail pressure sensor. My tuner suggested (from my description over the phone right after it started) it could be the fuel pump driver module next to the fuel cut-off switch or one of the cobra pumps. I am starting to worry it might be something else. When it stumbles the car backfires most of the time. Also, the plugs were well covered in carbon after this happened several times. A fuel pressure gauge hooked up to the fuel rails at idle indicates 43psi with the car sitting. I don't have a way to hook the gauge up with the car going down the road or loaded.
I plan on taking the car to a ford dealership to let a tech friend drive it and scan to see if they can diagnose the problem. Any other ideas? Can anyone here describe how their or a friend's cobra ran when the FRPS went bad? It would be nice if that were the only problem (~$65). The car is out of warranty (40,500 miles) and the drivetrain has been voided since 4,500 miles anyway (pulley change).
The history of changes to the car up to the time this happened:
1.) I put gas in at a mom and pop BP/Amoco 25 miles before this started (I have been using this station for over a year with no problems before). I have since put in new chevron gas, changed the fuel filter and added gas treatment and driven the car several miles, problem still the same. I have been changing the fuel filter every 6,000-10,000 miles.
2.) I installed brisk 15 series plugs like the ones many 03/04 cobra owners are running (GOR LGS 15) about one week ago. I have put around 800 miles on the car since then. Plugs smoothed out the idle and low rpm surging pretty well. I changed the plugs to some new NGK TR6s to try and elimnate the brisks from the equation for now.
At first I thought it might be the fuel rail pressure sensor. My tuner suggested (from my description over the phone right after it started) it could be the fuel pump driver module next to the fuel cut-off switch or one of the cobra pumps. I am starting to worry it might be something else. When it stumbles the car backfires most of the time. Also, the plugs were well covered in carbon after this happened several times. A fuel pressure gauge hooked up to the fuel rails at idle indicates 43psi with the car sitting. I don't have a way to hook the gauge up with the car going down the road or loaded.
I plan on taking the car to a ford dealership to let a tech friend drive it and scan to see if they can diagnose the problem. Any other ideas? Can anyone here describe how their or a friend's cobra ran when the FRPS went bad? It would be nice if that were the only problem (~$65). The car is out of warranty (40,500 miles) and the drivetrain has been voided since 4,500 miles anyway (pulley change).
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