Nissan Repair: loss of power, sputterring and stalling, nissan maxima, smell of gas

Question
Hello again sir.
 I own a  1994 nissan maxima with 89k. it has the VG motor. and is a V6 3.0
 I recently had a check engine light and the mechanic performed a tune up but the problem persisted. Then when he scanned it and it came up as a fuel injector code. SO he replaced the injector and the car drove like a dream. then gradually I felt a change in the performance from the first day. Each day I drove it after that i felt a slight difference in the performance. by the 3rd day i felt a vibration and feared another injector would be failing aswell so i used some chevron injector cleaner and went on my way. two days later the car didnt' start up right away and then the smell of gas was very strong. The next day when i drove it i did feel a slight loss if power. That night when I was leaving my friend's place the car immediately smelt of gas as soon as I started it it up, and it didnot start up right away as it had done so for the first few days following the injector replacement.  Then the car started sputtering and vibrating.  The mechanic lookeda t the car and checked the voltage on the wires and said he'd have to check the injector to see if it was defective but that the egr buffer wasn't supposed to be making noise and that may be why there's aproblem because of the "leak", as he called it.

After he checked the car it drove worse than ever before. It wouldn't stay on if I did not give it gas, and at lower speeds it would give me a few loud pings that felt like they were hitting right behind the gas pedal before it started to regain some power and speed up. once i hit 65mph it would then seem ok. but then once again it would begin to sputter and even stall once i slowed down for a light or turn.

He called me tonight and told me that he was almost certain the egr buffer was defective and that he needed to replace the injector because he was certain it was defective.



can you please provide me with some insight into what may be causing this loss of pwer, vibration, and stalling.

Thank you for your time and expertise.


Danny


Answer
Danny,

It is common for more than one injector to fail and when one fails the rest are soon to follow.  The EGR is a common problem and if it is not opening and closing properly that can add to the bed running engine.  No, the mechanic is not taking advanage of you in this case.  I have a 350Z and it did the same thing as you describe.  Two injectors later and the car was fine.