I have a 2002 Acura MDX my engine had oil in it so I removed the intake manifold and engine head and install new seals for the cylinders. I'm having a misfire on cylinder 3 but the coil spark plugs everything is new. I replace the ECU but it's still the same problem my check engine light with the vtm-4 light. Is there any advice I can get on this situation I'm running out of money at the mechanics I done most of the work myself but don't have the experience and where to look for the problem.

of course check for vacuum leaks, but realize engine work is VERY hard to do perfectly and any small mistake will cause misfires. Do a wet and dry compression of the engine to see if #3 has internal leakage first