I have low compression in my N/A right now, about to change engines but I need to know if I have just an injector problem or what.

The backfire after almost every shift is SOOO annoying!! And after ALOT of studying for this replacement and just learning more and more about my car I narrowed an issue of: very hard shuddering when running the RPM's over 4000 to 8000. When the car's cold the shuddering is SO bad that I can't take the car past 3900 RPM's (easy). But if the car engine is nice and hot, the shuddering is almost non existant. On some nights (cool dry air) the shuddering is non existant! I just hope that if I didn't correctly diagnose the problem, that it at least stays only a problem with my 178,000 mile engine! lol


Any diagnosi?

 

bump, any ideas?

 

Not even 1 person has a hypothesis? No one has had this problem before?

Well geez!