help!! unusual knock
 

Well first of all my truck has 167,000 miles stock fuel system and injectors were never done. It has no programmer. My problem is occasionally apon acceleration there is one single kock followed by a puff of white smoke out the exhuast its seems to be happing more and more often lately by that i mean every 10 or 15 minutes of normal stop go driving it sounds very similiar to an injector knock when an injector failes, but the wierd part is its just a single knock. Im stumped and need help and thanks.

I would guess you have a failing injector...

I would be careful with it if you're seeing white smoke...

Thanks for the response i actully pulled the injectors come to find out for some reason the first one i pulled the hold down bolts were loose causing the copper crush washer to not seal properly the injecter is getting tested today hoping i can still save it. It seems very unusual to me that this would loose seeing as how they are the stock injectors.:humm: