Well i need some help guys. I have a zz4 Gm Crate engine. The car ran fantastic for about 5 years now. I had a touque Converter break on me and i pulled out the motor and trans and had the a new trans intalled with a new torque converter. When i pulled the motor i had to take out the distruber because it was hitting the firewall when i was pulling the motor out. Everything was installed back and car ran and i drove it home from my buddy's garage.

With all that info being said. I went to drive the car to work and i noticed it was missing real bad at high RPMs. At the lower RPMs it sounded fine but i could see the tach needle bouncing and it sounded like that miss was still there. So everything i read said it sounded like a cracked cap or rotor. I bought a new cap and rotor and it did the same thing. only now it didnt want to start for me. It started backfiring through the carb. I thought perhaps i had a split in a spark plug wire. I bought a new set of wires and it does the same thing. Someone told me it oculd be that vacuum control module on the distributer. I changed it out and it still does the same thing.

I have the firing order set correct and double and triple checked that all wires are connected. If i dissconnect the vacuum advance hose from the distb. it runs perfect. Smooth sounds great. As soon as i connect that hose it starts missing and backfires through the carb and shuts off.

What the heck do i have to do here? im pulling what hair i have left out over this. Please someone out there offer me some imput.

 

When you put the dist back in, are you sure you set the timing right? Maybe it's too advanced, and the extra vac advance when u connect it, is causing the grumpiness.

Could be a bad vac can diaphragm, but u said u changed it. Does the problem go away when immediately you pull the hose from the can, or only when u plug the hose?

Was idle speed and TV cable set correctly when u put it back together?

 

Is there something grounding out in the distributor?

 

Look at the rotor; make sure it hasn't hit the inside of the cap, and bent the little contact tip off to the side.