WHAT'S THE PROBLEM??? please help

[BOOSTR]

P0171 could be MAF, but most likely its your wastegate. See the pdf in the ProtegeGarage section on here. P0421 is most likely caused by your catless pipe(especially since you are not using the MIL or antifouler method) but could also mean your sensor is bad(doubtful with 51K).

Quit driving the car aggressively until you check and replace the WGA if needed. Install either the MIL or antifoulers. Clean your 02 sensor. Change your plugs if original.

 

[msp_rad]

P0171 could be MAF, but most likely its your wastegate. See the pdf in the ProtegeGarage section on here. P0421 is most likely caused by your catless pipe(especially since you are not using the MIL or antifouler method) but could also mean your sensor is bad(doubtful with 51K).

Quit driving the car aggressively until you check and replace the WGA if needed. Install either the MIL or antifoulers. Clean your 02 sensor. Change your plugs if original.

the wastegate was changed under warranty about 3000 miles ago,
if its the maf, than why doesnt it throw a cel with the stock air box???

 

[BOOSTR]

I cannot tell you why as I was not involved with the install. But that said I would try cleaning the MAF & 02 sensors
install the MIL or antifoulers, replace the plugs & pcv and confirm that there are no vacuum leaks first. Reset the pcm after doing all of that and go from there. I am not suggesting that you replace either the MAF or 02 because of the cels. A can of electronics cleaner, 4 plugs, and a pcv are a lot cheaper than a MAF and 02 sensors.

 

[msp_rad]

I cannot tell you why as I was not involved with the install. But that said I would try cleaning the MAF & 02 sensors
install the MIL or antifoulers, replace the plugs & pcv and confirm that there are no vacuum leaks first. Reset the pcm after doing all of that and go from there. I am not suggesting that you replace either the MAF or 02 because of the cels. A can of electronics cleaner, 4 plugs, and a pcv are a lot cheaper than a MAF and 02 sensors.

you are right, and make some good points.

just wanna thank you for all your good advice!!!!!(headbang)