I recently started having a problem with what seems like a studder or surge only in 2nd and 3rd gears under moderate acceleration. I have been told that the timing may be advanced too much. Under full throttle acceleration everything is fine. The only mod on the car rite now is a 255 walbro pump and a K&N filter. I would like to get this resolved because I am getting ready to install a P1-SC and 3 core intercooler, along with some bosch series 3 -39# injectors and a pro-m calibrator.
Help Need more input here has anyone had this problem? I have cleaned the maf with no change, and it shows no codes. Runs great wide open.
I've been told the Walbro pumps may cause surging since they are not designed for returnless fuel systems. A have a friend that had similar surging problems on a blown car and replaced his walbro with another pump (I can't remember which one though sorry) and the surging went away.
So you think it is a lean or rich surge rather than a timing problem? The only thing I've noticed different since putting the 255 pump on is about 2mpg better fuel mileage from 21 to 23 on the hiway. I've also heard that the computer on the 99 cobra can self adjust or compensate for some minor mods and variable conditions (heat-cold-altitude). How does that work with a programed chip for a blower? Does the chip disable some of the variable functions of the computer?
