Hoping someone here can give some insight, I'll try not to sound vague without an error code. I'm going to run up to the parts store later and have them scan..

Have an 05' GC 3.7 v6 and I have a check engine light. It stays on all the time, except if I floor it at any speed it starts flashing and feels like its sputtering or misfiring. It doesn't jerk hard or make any noise, just feels like its trying to go but doesn't quite want to. On top of this it's telling me to check my gas cap on the dash. The cap is definitely closed, I'm wondering if the two are related, maybe emissions? Again, having the specific code will eliminate my guessing but until then, any guesses? Thanks in advance.

Upgrade from a 99 to an 05 and I get welcomed to the wide world of electronic sensors

 

Get the code and report back. My crystal ball dropped and smashed...

 

You can do the "key scan" trick. Turn the ignition key on until the warning lights light up, then off, then on, then off, then on and wait. The codes will appear in the odometer. On, off ,on, off, on.

BTW, my 2000 is a new as I'm ever going to go. This one is about as complicated as I ever want to get.

 

A flashing check engine light is telling you the catalytic converter is in imminent danger due to an overly rich mixture. Find out what codes are stored and active, then report back with the codes.

 

Haven't known of the overly rich issue by itself, however, under acceleration or other parameters a flashing CEL normally indicates a misfire or preignition/detonation..

Which does in turn dumps unburned fuel into the cat, and raises temp. Poor quality/too low octane, bad plugs or wires, ignition coil are normal culprits.

 

P0442 evap emissions. The guy told me the code, and I started to ask him to elaborate and he said Im not sure...and put the scanner away. It has a weird aftermarket gas cap. Going to run to the junk yard tomorrow and get the original.. If I had a closed space and decent tools I'd be more confident taking this on myself...Thanks for the input guys, appreciate it.

 

An EVAP code isn't going to cause the light to flash under hard acceleration. Buy a new gas cap, a junk yard cap isn't going to work. When was the time the engine was tuned up?

 

Agreed about salvage gas cap, my GC had a locking aftermarket cap and I wanted an original so got one from a salvage that looked good put it on got the check engine evap codes put the other back on and it stays off.