Hey guys I drive a 1999 zr2 blazer with the 4.3 vortec. The motor was changed to a 2006 (I think) 4.3 vortec by the previous owner. This truck has been nothing but problems from day 1. The truck got to a point where it wouldn’t crank. I put in spider injectors. It will crank fine now but has a vibration at idel and the motor shakes a lot. Past 40mph check engine light blinks. It reads a cylinder 3 misfire. I have changed all the plugs, wires, coil, the distributor cap and the rotor. Does anyone have any ideas on my issue. Did I not pop in one of the pop its on the spider injectors good? Any help is appreciated! Thanks again

 

Welcome to the forums. Start by checking fuel pressure. Good place to start. https://blazerforum.com/forum/tech-a...e-first-30093/

 

After the fuel pressure, check the distributor gear for excessive play/movement. The distributor gears are noted for having alot of wear and causing misfires in 4.3's. Can you scan it and look at fuel trims. This can tell you if you have a vacuum leak. Your fuel trims should be around 0. If they are above +5 or higher look for a vacuum leak.

 

I feel stupid, putted the intake manifold back off and on of the injectors was not pushed in good causing the misfire. Thanks for the reply’s!

 

Lol glad you got it figured out before you started throwing money at it!

 

Anyone know why my brand new ac compressor is not kicking on it has no Freon in it but how can I charge it if the compressor is not coming on?

 

It will take freon from a pressurized can to get enough pressure in the system to get the safety switch to close. Then the compressor will turn on and keep the low side pressure down so you can continue filling the system.