My Friend has a 95 Z28, he noticed that it wasn't running right for awhile, it was missing, but the other day it got really bad. It misses really bad now, and stalls right away and you can smell that the exhaust is really rich, it's not driveable. I'm used to working on low tech cars with carbs and no computers, I'm thinking that it's the opti, the car has high KM's, but I'm not sure if that's the problem. Thanks for the help.

 

I wish I could give some more info, but that’s about all I know, the car is stock except for MSD ignition and exhaust. I'm still thinking that it's the opti, I think it's not getting proper spark, but I'm not familiar with computer controlled cars, I haven't had to work on my Formula yet. Any help would be appreciated as I told him I would help him fix his car.

Thanks

 

Start with the cheap and easy stuff first. Pull the plugs and see what they look like. If they are bad, which they probably are since you say you can smell gas. Put new plugs in and see what happens. Check the wire while you're at it. Did the car run good right after the MSD ignition was put in? If the plugs, wires, and MSD is good, then it appears to be the opti.

Bad gas maybe, but doubtful unless it has been sitting for a while.

 

I had a missing problem, turned out to be a big air leak. Since its running rich check the plugs and wires like Joe said. But i would probably have to say its the opti, and again like joe said, start with the cheap stuff becuase the opti IS NOT cheap. Good luck.

-Nined3z

 

My 97 was doing that it runs rich cause of no cats on mine. I have a bad ground wire somewhere and I also opened the throttle blades and the intake was full of caron so maybe taking the throttle body out and giving it a good cleaning and the intake.

 

could very easily be a bad o2 sensor when they go bad they mess up the air fuel alot

 

that could cause the foul smelling gas and rough running, but o2 sensor will not affect startup cuz the pcm doesnt use the 02 sensor until the car has been running for a bit. So check the electrical things like others said. I wouldnt discount things like injectors or fuel pump, but those are less likely given the history.

 

Thanks for all the help, I'll be sure to look into the other things before we go and replace the opti right away, hopefully it's somthing cheap, he can't afford a big repair. The MSD has been on the car since he bought the car a year ago, and it ran good up until about a month ago, then it started to miss, and it wouldn't be bad gas because he's gone through few tanks since it stared.

 

he didn't by chance take the car to a car wash or run though some deep water. Car wash places that spray water from the bottom will take out an opti everytime.

 

I forgot that before it started running bad that it failed the emission test, so we knew there was something wrong already back then. I don't know about the car wash, I'll have to ask him about that, we do have a car wash around here that sprays under the car, I know he’s used it, but I don’t know how long ago.

 

I had my opti die a few months ago, this may help out some.

It started out as a miss only under load, like when the converter was locked up and I was going up a hill. Then it started missing under normal driving conditions. Finally it started missing at idle and under any condition. I got my raytech gun out, and checked the temp on the primary tubes on the headers, and found that #7 wasn't firing at all.

Do a search for Jason Cromer, you can get an opti through him for about $220 I think? That is if you decide that it is the opti........