Hello. I have a 1994 Z28 with minor mods (see sig.) and am having problems with a hesitation. I replaced the driver side O2 sensor and decided not to do the passenger side because it looked like a PITA. The car drove fine for a little bit (a couple months or so) and developed an ever worsening hesitation. Until today it would drive fine sometimes but most of the time it would hesitate from about 1500 rpm to 22-2300 rpm, from then on it would be ok. I replaced the fuel filter today and now it hesitates from idle through 3k rpm if you step on the peddle more than just a touch. I plan on cleaning my air filter soon as a precaution as well as putting on that passenger side O2 sensor. I also would like to replace the coil and do the ICM mod as well but heat does not seem to play a roll in this (it does it when the engine is hot and cold does not matter). Can anyone help me with this problem hoping not to have to replace the opti but need to find the problem. BTW motor has 130,xxx miles and the opti was replaced around 55,xxx

BTW~~> The fuel filter had not been replaced since 1/3/04 and the air filter has not been replaced/cleaned (K&N) in almost 2 years. I also seafoamed it a few months ago, ran it for 500 miles or so and changed the oil, the other O2 sensor went in after the seafoam. FYI Hope this helps.

 

can anyone help and tell me an easy (well easy as possible) way to change the passenger side O2?

 

Do you have access to a scanner? If so, scan it to see if there are any trouble codes. You can also see if your o2's are changing like they are supose to.

Sorry I can't remmber how to change out the o2's on stock headers/y-pipe.

ZMAN

 

UPDATE... I reset the PCM so it would "forget" its air/fuel mixtures and it now runs pretty well. What does this point to? Any help is appreciated. My neighbor might actually have the scanner still so ill have him look at it too. He is a mechanic for a cadillac dealership so I guess his input might be well worth it. Thanks for the help.

 

O2 socket and a ratchet. There is just enough room.

 

Well after days and days of trying to figure out what was wrong we hooked up a fuel pressure tester and it only read about 20 p.s.i. at idle so that appears to be the problem (at least lets hope so). Thanks everyone for your help im so relieved to figure this out now i have to worry about replacing the pump