Whipple is on, but there's a problem :/
 

I picked up my car yesterday, and before I drove it more than a block the CEL came on. Took it back and the codes said that there was a misfire in bank 4 at start-up and then it caused it to run lean.

Restarted it and everything seemed ok, so I was told to take it home (2.5 hrs away) and to call on Monday when someone who could help was there. I drove it and it seemed like everything went perfect, but then I stopped for gas and it happened again. Cleared the codes and continued home without any issues. Even when it first happened and I had to drive it back to the shop, it seemed to run okay despite killing my nerves.

Any ideas what this could be? They checked the plugs & connections and everything seemed okay, and I read somewhere that it could be a timing issue. I am using the FRPP tune.

Another question - when I first left the shop the A/F ratio was ranging from 12-13, but by the time I got home it was showing at 15 and spiking up to 16 (just normal driving, not under boost). Is this normal, could it be because of the length of the trip? I was going to ask on here for help with what kind of numbers I should be getting on the A/F gauge.

Think it's safe to drive the car today on some errands that have to get done, or should I just hold off? I'd kind of like to see where the A/F level is now too. Like I said before, the car seemed to run fine when the CEL wasn't on. (when it came on it seemed fine too even though I would just pull over and clear it)

A/F wants to be rich, 11.5 under hard load is a good number for FI. Normal driving isn't really worth monitoring as it jumps all over the map.

Regardless how some folk extoll the virtues of canned tunes, you simply cannot beat a dyno tune.

Be Careful with that motor until you get this issue resolved. Normal driving should be fine but stay out of high boost/RPM.....

Why they gave the car back to you in that condition and make you drive 2.5 hours each way to return it to them to fix is another question I would be asking. That is unacceptable. I would have left the car there and demanded that they call the manager to work something out.

agreed, that is something they should not have done. They should have kept it at the shop and fixed the problem.

Excellent point!!!! Like other have said, stay of boost until the A/F issue is "locked" down. Good luck & let us know!

Thanks. I wasn't sure i if it mattered if it wasn't in the boost because of the vacuum.

Yeah, I wasn't too happy about taking the car home, but they couldn't reach their manager because he was flying in from Vegas. I was ready to just get in a cab and go to the train station, but they assured me that it was a startup issue and if the light didn't come on it should be okay. It didn't happen when they test drove it and I believe that because it didn't go on every time for me. I would've left it anyway, but I had a family obligation ihad to get to last night, and I dont't think I would've made it if I had to try and find a way home on the train. (wouldn't want to piss off my wife after getting a sc put on)

I know the FRPP tune is canned, but I don't feel like their's is just another canned tune. I have faith that they put a lot into developing it, and I haven't heard anyone complain about issues with it. I wasn't't trying to get every spare HP I could get. (yet)

I don't think the A//F is an issue...I wasn't seeing those numbers under boost. It was during normal driving and I didn't know what I should be seeing on the gauge then and how it would be jumping around. When I left it was bouncing around between 12 and 14, but towards the end I noticed it seemed to be higher. I didn't really go into the boost after the beginning of my my trip because I was basically cruising on the highway in traffic.

I think I should try it again to see what is going on now that I know what to be watching for. I tried searching for info on is but could never really get an answer as to what the gauges should be showing and when they should be showing it.

The Ford canned tune isn't the issue. I'ld look someplace else for the issue.

check for pinched or loose wiring especially around the coils.

Your long term fuel trims were adjusting during the drive, it's normal. Maybe you got a bad plug or need some silicone around the cop? You could try calling Whipple tomorrow. What about driveability? Does is stumble or vibrate unusually?