Quick question on what may be causing this. A d15B motor stock w/ i/h/e nothing has been touched cept the header i removed it about four days ago. Drove fine after i reinstalled for about two days. After that car starts up fine. But in idle u can hear the backfiring/bogging of the car. It revs all the way to its RPMs but not as fast as usual. The whole way thru the RPMS the car sounds like a STI. All its missing is a bodykit and u can say i have subaru engine . I was thinking that the injector might be dirty?. Engine has oil (not recently changed though) I even added high octane gas to see if it would clean the engine ( if the gas before it was bad or what not). So will some fuel injector cleaner work?. The car idles fine but with the rough STI sounds and doesnt perform how it used to as far as WOT but it reaches it RPMS just not how its supposed to .So what can be causing this problem? Ideas?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 92EG8 &raquo;</TD></TR><TR><TD CLASS="quote">Quick question on what may be causing this. A d15B motor stock w/ i/h/e nothing has been touched cept the header i removed it about four days ago. Drove fine after i reinstalled for about two days. After that car starts up fine. But in idle u can hear the backfiring/bogging of the car. It revs all the way to its RPMs but not as fast as usual. The whole way thru the RPMS the car sounds like a STI. All its missing is a bodykit and u can say i have subaru engine . I was thinking that the injector might be dirty?. Engine has oil (not recently changed though) I even added high octane gas to see if it would clean the engine ( if the gas before it was bad or what not). So will some fuel injector cleaner work?. The car idles fine but with the rough STI sounds and doesnt perform how it used to as far as WOT but it reaches it RPMS just not how its supposed to .So what can be causing this problem? Ideas? </TD></TR></TABLE>

when was the last time you did a tune up?
also check the pcv valve, when they are clogged this problem occurs.

 

well i had the same issue, sounded like an STI. I changed my fuel pump/strainer, ran some seafoam through the tank, adjusted my timing, and retorqued my sparkplugs.

 

PCV Vavle is the Valve on the backside of the intake correct? Also I bought the motor like 2 months ago and swapped it in myself no problem since then.

 

under the IM, depends on the engine. However call me crazy, but i removed/blocked off my EVAP system, and it almost seems to have cured the issue.

 

check the timing man my friends car does that too