#6 misfire

A friend of mine and I replaced the intake gasket b/c took to a auto place and they pressure tested car and said the intake gasket needed replaced...got car put back together and started car and it was shaking badly...he has a diagnostic tool and it showed random misfire and o2 sensor...we replaced plugs and wires and started car and ran great so replaced o2 sensor and started car and shaking continued and code read #6 misfire...check wire at distributor cap and got fire checked plug and no fire so replaced again...car still #6 misfire and code for too lean fuel...at wits end and need car for work...can anyone help...
:runaround:

Welcome to AF, what year truck and engine is this? an injector could be doing this, maybe.

Info, like Max requested would help......

Sure wires are going to the correct plugs?

Check for spark at the end of #6 ignition wire with a spark tester?

Swap number 6 plug with another to see if the problem moves......

Then check compression.....

Then check injection system.......if CPI(one injector), could be plugged poppet valve or leaking leg to poppet valve......if SFI(6 injectors), #6 injector could be bad or connection/circuit to it.........

The outside possibility is the gasket installation....

Air leak? Spray brake clean around #6 intake port.