hi, my car was running fine the last half year, suddenly the afr's went to 16-17 in cold start and slowly return to it's normal 13.6 , look for vacuum or fuel
leaks but all is fine. The pump sound like always (walbro 255). The spark plugs
looks fine.

think in replace:
1-fuel pump
2-fuel filter
3-drain the tank
4-burn a new chip

any help, thanks

 

Mine does that sometimes but only momentarily. How slowly is slowly? Are you running a basemap only?

 

i mean like 15 seconds , and yes is tuned, before he start in 13.0 and goes to
13.6


333whp/241tq@14 psi Dynojet, for DD

 

That's just idling yes? Mine starts at 14.7. Sometimes it starts lean but only while idling. I would be worried if it STAYS there. To be safe call the tuner and ask.

 

Do you have an AEM wideband? Mine used to do that all the time on startup it would read high then come back down. I cleaned the sensor and that seemed to help.

 

yes only at idle, i have an apoinment for wensday with the guy who help me with the tune. I'm try to fix the problem before that day if it's a mech issue
because the mechanic is done by myself and now i'm lost.

 

yes aem wideband, i try to clean the sensor today.

 

Try the Forced Induction forum....you'll get more help there