I have a '95 Z28 with 136k that developed a bad vibration ( I can watch the motor rock back and forth) from what I guessed was a misfire. I replaced the cap and rotor, distributor, plugs and wires, fuel filter, fuel pump, and The ignition module. Still has the problem but worse. Its turn key and will drive but not in any way that's safe for open roads. Took it for a test drive around the neighborhood and with the pedal to the floor it takes about 40-45 seconds to get from idle to 1800rpm. It bogs bad. Once it hits 1800 the rpms build like regular and power is restored until it shifts (auto) and the problem starts all over again. Forget about going up a small incline. 5mph max. I got it home and popped the hood to find the passenger side exhaust manifold was glowing hot on what looked to be the back one or two cylinders. What the he'll is wrong with my car?

 

How sure are you that the opti was placed correctly and that your wires aren't crossed? Have you scanned for any codes?

 

the opti only goes in one way check your wires if there good pull the plugs and check them out... but get it scanned first

 

Had the ignition checked out at a shop, I have a scanner and it's not throwing any codes.

 

your running rich on those cylinders, unburnt fuel is burning in the exhaust. i would assume the motor is flooding at idle and once enough air is getting in at more throttle the missing cylinders are firing. have the injectors cleaned and flow tested at a injector shop.

 

The opti is "suppose" to go in one way, you'd be surprised how many are able to get it on and still have it misaligned.

 

yep and when you put em in wrong it usually ruins them because they were forced on and the shaft pushes into the opti or the opti itself is bent. i would add to my last post that the op should do a compression test on all cylinders.