when i bought the vehicle it had a stillen intake and catback exhaust already on it (love the way it sounds) well it ran fine except for a messed up injector. (thats what i was told). i swapped around the coils to make sure and sure enough i had come to the conclusion that it was an injector. well whenever u got it on the high way there was an annoying helicoptering sound from the exhaust because of the dead injector. well im no light footed driver so i was on my way home from school a week after i bought it and wanted to see what she would do. after my hard run thru all of the gears i could only manage to get 120mph out of her. pretty good cause i was running almost out of 5th. but after that the helicoptering stopped and she ran like a champ all the way home way more power. im guessing that the injector came back alive. i mean it ran amazing. the guy that sold it to me wanted to buy it back. it ran that way for about 2weeks then started back to the helicoptering so i figured the injector was out for good. i decided that i might as well fix the injectors. so i took it to a shop in charlotte.(not saying who unless u pm me and want to stay clear of them.) i really like the shop and he worked on nice vehicles so i was like ok ill do. i bought the injectors off line because they were way more affordable than what he was going to charge. he said that he couldnt warrenty the part just his labor. that was fine with me cause i understand that especially from a business stand point. well he did the work and i had my dad go pick up the car for me. the mechanic couldnt get it started and was pissed. so he keep on trying to start it turning the starter for minutes at the time. anybody knows thats not normal or good for a starter. so since its a manual my dad pushed it out of the guys shop and popped the clutch down a hill a couple of times to get it started. it was smoking like crazy and i just told my dad to drive it home and not rip the guys head of just yet. well i went home to get it and the car still was hard to crank and smelled like raw gas when started it idled normal ran like a bat out of hell, but it smoked the world up. so i was pissed and decided to take the plenum off myself and take a look. the mechanic had ripped every single upper and lower o-ring on each injector. it was flooding the engine so bad that i smelt gas on the dip stick. so i changed the oil asap to find gas pouring out with oil. not a good thing seeing as tho cylinder wash out was occuring and that will kill an older engine really fast. this is were it gets weird (atleast to me). i replaced all of the injector o-rings and put everything back together. the car was still a little hard to crank but not bad and the idle was eratic. ran like a champ once u got into the throttle and didnt smoke a bit. well i have been driving it just the way it is for the past 3months and it has grow worse. it now backfires like a massive 50 calliper rifle is shooting out the hatch
. so bad that it blew pieces of my cats out the exhaust and cracked the exhaust before the cat. i was getting tired of driving it around like that and have ohmed everything that i know to do. vaccum is good fuel psi is normal all injectors are firing as well as coils the only thing the ecu is saying is running richon right side. the only thing i can think of is that another o-ring has ripped. but why know. so here is were it gets fun. i maxxed the tps sensor as far as it would go forward tightened it down and then went to the iacv and turned the philips head screw almost all of the way in. and unplugged the yellow connector. the car cranks better than it did and sometimes idles perfect but runs like a charm with only a backfire here or there. ive clean the iac new o2 censors. fuel pressure regulator and dampener. could it still be a leaking injector now. by the way its a 93 300zx VG30DE. thanks for the help and sorry about the story. more insight the better i always think
