[AP7]

My car's been acting really wierd lately. It stumbles when I put the pedal 2 the metal. Especially in 1st, 2nd and 3rd gear. It sounds almost as if I'm flipping the gas pedal on and off really fast all through the RPMs... And it has been back-firing like crazy; every time I let go of the gas and the clutch is still engaged: Pop! Pop! Pop! Pop!!!! It sounds cool and all, but it's starting 2 worry me.

What could this b? Do I need new fuel pump and or injectors? Re-program my Diablo Chip? Any ideas?

Here's a list of the current engine mods:
Diablo Chip, ICE-MAN intake, FC 65mm TB, FocusSport Race Header, FocusSport exhaust, AF/X UDP, Venom Cam Gears (dyno-tuned)

 

[AP7]

^Bump!^

 

[AP7]

Here's an eMail reply I got from Justin Shenk:

"I was reading your post on FocalJet and it wouldn't let me post because my account is too new. I was reading about your engine stumbling which is a big problem. I had the exact same problem with my Old focus many times. I think what caused mine was one of the cam gears was slipping badly that's after i had it dyno-tuned as well. Other than that You mioght want to post what if anything was the last thing you did before it started like any mods you recently installed or if you noticed it right when it staarted or if it happened eventually. If you remember where your cam gears were set check them and see if they have slid at all also feel if the engine is producing a lot of heat that's what mine was doing. Other than that i wouldn't know what to suggest."

Well, it could b that. But I had the gears installed and tuned almost a year ago! I have never had any problems like this with my car 'till now. And I haven't modded it since a while ago. In fact the latest thing I did was remove the air box resonator and tweaked the TB 4 a lower idle (4 better gear braking) about a month ago. I'm gonna remove the chip and see if that makes a difference... Maybe it went bad? If not it has 2 b something with the fuel delivery... Anmybody else have any ideas?

 

[belnaper]

the focus also has a known problem for the filter in the tank geting pluged up causing a lean condition. that can also cause a back fire consern. But it sounds more like what he says a timming prob.

 

[robbdj]

I'd try pulling the chip first, I know on other platforms (ie. Ligthnings) we've seen those Diablo chips cause some serious platforms.

 

[TheTrueChAoS]

Pull your tps sensor and see what happens.. This just happened to me and i lost tons of power and everything and then i took that tps out and it really opened the engine up and stopped almost all the back firing