[knnx47]

Chk eng lt came on( daughters car) 2003 ser 2.5...took it to autozone to read code...misfire chk 3...changed all plugs with jfk iridium and put in new spectre air filter....car was hesitating and shaking under 3k rpm and low power on takeoff....put new stuff in and was fine intially...daughter left to go and called 20 min later back doing same thing......don't know what to do next....need help...thks

 

[JP]

maf, vacuum leak.

 

[99sel-r]

remove spark plugs and check for coolant on pistons. If there is coolant your head gasket might be going bad

 

[i68k]

you got a misfire on 3, did you change or swap your coils yet to determine cylinder 3 coilpack failure? i would also replace cam & crank sensors to newer metal type sensors if you havent already, check the vin for recalls. the 02-03 ser have the most recalls, in case you missed one of those recalls, they change cps sensors for you and reprogram ecu.

 

[SHIFT_03SPECV]

swap the coil packs around from 3 to 1. clear the codes, if it come back on 1 then you have a bad coil pack. also have the dealer run your vin for the recall.

Search for precat failure on here and read up.