Hit rev limiter now wont run

[SVTsteele]

Hello i am having an issue with my 04 cobra that i just bought 3 weeks ago. It has 64k miles on it had some overheating issues to work out but other then that has been running great for me. On my way home this week i revved my engine at one of my buddies on other side of highway and hit the rev limmiter ( have done it a few other time with no issues) as soon as i let off the car died and wouldnt start back up until it cooled down some. As soon as i got it to restart it is running real rough, idle will surge up and down until it dies. Got it home cleaned maf, iac, couldnt find a vacuum leak, checked plugs, oils good coolants good. It threw P0171,P0460,P0755 codes. It will now idle very rough still surging but not dying right away with my wideband pegged at 10 smells raw fuel and smoking a little bit out tail pipe. I tried searching but havent found what i need, any help is greatly appreciated. I finally got my dream car and just want to get it back on the road again.

 

[Onelfastlride]

Its not a good thing to bounce off the rev limiter nor do it on purpose. That being said, I wonder if you blew the FRPS. (fuel rail pressure sensor). It can happen when you hit the rev limiter. Without an FRPS the car will have a hard time running and maintaining proper fuel pressure.

The rev limiter on the Cobra isn't like an MSD box pulling timing, the Cobra rev limiter pulls fuel and can cause issues like a blown FRPS.

 

[MrSwa]

Its not a good thing to bounce off the rev limiter nor do it on purpose. That being said, I wonder if you blew the FRPS. (fuel rail pressure sensor). It can happen when you hit the rev limiter. Without an FRPS the car will have a hard time running and maintaining proper fuel pressure.

Sounds like the FRPS to me. I had one go out and the car ran terrible. It also acted flooded after driving and needed a cool down period. Super easy fix if that's the case.

 

[NastyNate420]

pull the vacuum line of the FRPS and see if there is gas coming out. if so the badder failed and its bad.

 

[BlksvtCobra01]

I agree with all posted sounds like the FRPS. Pull the dipstick and see if the oil smells like fuel too.


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[Bdubbs]

When I blew my frps the vacuum line didn't smell like gas. So if it doesn't smell like fuel, that doesn't mean it's guaranteed good.

 

[SVTsteele]

Ok i will definitely look into the frps, i started the car upearlier before i left and it fired right up but has a miss at idle. It wasnt surging and afr was back around 15 where it was before. This is confusing me as this is a little better then what it was doing at first, then the next day and this morning was when it started smoking whlie at idle so i thought the problem was getting worse and now it goes back to slightly better(not surging now) then it was when it first had an issue? Its got to be some sort of sensor thats not getting a proper reading or something like that right?

 

[SVTsteele]

When it was smoking and i tried to rev it a little bit it sounded like a Subaru and wouldnt get over 2.5k, now even with what seems like a miss it revs up with no problems and sounds fine, with the exception of what seems like a miss (engine running a little rough and can hear the occasional stumble and or pop from the miss).

 

[Blown38]

I would check the compression. may have broke a cam gear bolt.

 

[RichM1983]

When I blew my frps the vacuum line didn't smell like gas. So if it doesn't smell like fuel, that doesn't mean it's guaranteed good.

I had the same thing happen. FRPS didn't cause any fuel in oil or vac lines but it was bad.

I'd bet that is your problem. Before you get to worried swap it.

 

[CompO_Eric]

Unplug the FRPS and see if it idles fine. If it does then it's blown.


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[SVTsteele]

So i went to the junk yard and picked up another frps from a v6 (all supposed to be same sensor) and its running exactly the same idling and revving as it should be with a slight miss every 10 seconds or so (im thinking that from the way its been running maybe fouled out some plugs so i will be replacing them). I just took it to the store and it ran fine, i never got on it hard but it seemed to run fine. So the question now is that i dont know what the problem was so i dont know how to fix it. I dont trust it not to do it again and leave me stranded on the side of the road again.

 

[Bdubbs]

Check plugs, and please don't be buying used frps! Who knows if that's any good. It's a good idea to keep a spare in the car with you anyways.

 

[RichM1983]

Did you check to make sure your oil wasn't full of gas before you drove it?

 

[hotcobra03]

The codes you posted are strange..

460..fuel level

755 auto trans code..

po171 is common..

I had my first engine issue at around same mileage. .


ive neen bouncing off limiter for 13yrs never had issues from it..

what mods have been done to car if any
.

have you cleared pcm after changing frps?

After clearing you need to drive car to complete a drivecycle..


a compression test is a must on these when having issues.

I had a blip in idle that seemed to go away after coil replacement.

mine is stock .I use oem plugs..have about 175k on set now and car purrs

 

[SVTsteele]

I only got the used frps to test because i didnt want to throw away $100 if i didnt need to if that wasnt the issue. Oil seemed fine, ill try to replace plugs today if i can, i cleared the codes and they never came back, i thought they were weird codes as well. Longtubes, x pipe, magnaflow, 3in pulley, cai, egr delete and tune are the mods. I drove it to work today being easy on it and it seems to be going fine but havent gotten on it hard but does seem slightly low on power but like i said havent gotten on it hard.

 

[BMSTNG]

SO how do you know the used one is good? Did you disconnect the vacuum line from the frps and run it to see how it runs?

 

[KenCobra03]

I just had a blown FRPS and it flooded gas everywhere. Out my air filter and loaded gas in my engine oil.
I also crapped out my spark plugs. It runs great once again thou.

 

[Jomo1994z71]

Always keep a spare Frps in glove box

 

[SVTsteele]

I unplugged the vacuum from the sensor and it still ran, i even revved it a little bit and it still ran. Ive been driving the car all week got on it hard today and ran great. Im not sure what the issue was.