Problems with 94 Cobra


New Member
May 7, 2010
Hey guys, I've been doing some research and trying to figure out where to post this and I figure this is the best place.

I have a 94 Cobra that's having an issue. It started doing this one night after I revved up at another mustang, as a sign of respect. I didn't take it over 4 grand but ever since that night it started running bad. It idles pretty decently but when I'm going down the road, just free-wheeling to keep my speed, the car begins to miss and runs rough. If I give it more gas it falls on it's face then surges pretty hard and begins running better (sometimes it backfires through the throttle body). I also have found a way to keep the car running better by letting off the gas, when it begins running bad, then immediately giving it a little gas and it smooths right out but this only lasts about 10 seconds before it starts running bad again (it feels like it's "missing" and a few cyls. aren't firing properly).

So naturally we thought it was an ignition problem. I've replaced the distributor, coil, plug wires, plugs (motorcraft stock cobra), ignition module, mass air flow sensor, fuel pump, and fuel filter. Next thing for a change is the fuel pressure regulator although we aren't getting gas coming out of the vacuum line or anything. We've blocked off the EGR with a plate (car has full flowmaster system from headers back).

The car just feels like it's not getting enough fuel so that's why we think it's a fuel pressure regulator or a bad injector. When we pulled the codes from the check engine light we got some O2 sensors saying the car is burning both lean and rich and the fuel pump has some sort of an electrical problem (swapping it out didn't do a thing, naturally).

Anyway, sorry for the wall of text I just wanted to be as detailed as possible. I need help from someone that's way smarter then me! Thanks in advance.
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