Start off give you some info on the car it's a 1989 ford mustang started as a 2.3 and swap it for a 5.0 connecting rod bolt broke and cracked the block got a engine out of a 97 explorer with gt40p heads fake cobra intake some upgrades from the 5.0 stock checked the crankshaft end play everything looked good so I change some gasket and seals didn't want leaks the motor starts and runs but not smooth a little shake and I get a small back fire sometimes I did the timing and checked the wires no vac leak I can see or hear going to start it and spray water on the lines to check them want to know where and if you can get your sensor tested And the ECM tested

 

check for codes, recheck firing order. could be a dirty maf or fuel related but rule out any code related problems 1st then work from there. No need to shoot in the dark.

Also ( just finished dinner and was thinking) make sure you are not 180* on the dizzy, check the rotor position or restab it. recheck all the connections and you may need to wiggle/recheck the salt/pepper shakers ( 10 pin connectors next to the intake) they cause some problems.

 

I'm try and run codes if I can find someone to do it check engine light is not working