Hello all new to posting here but I've been searching for days trying to find an answer and came up with all dead ends.

Let me start with the jeep. 2000 Cherokee classic 4.0 auto 4x4. I bought it drove it two days and developed no oil pressure and bad rod knock, so long story short new engine time. I came up with a low miles 1999 Cherokee engine. I knew going in the difference in distributor and cam syncro and no spots for coil to bolt, no big deal.

I got the motor put all new gaskets top to bottom new timing set and not planed but after I dumped them all in the floor new lifters.

I made sure dots lined up on new timing set as had done the job on my other cherokees. Get all my intake sensors and mounts changed over and set the new motor in. Put all front dress on grounds crank sensor o2s all that good stuff and filled with coolant.

Go to start the engine it fires maybe 3 times then backfires though the intake. No big deal maybe I just got it 180 out. Bring it back up on tdc compression stroke cam sync with the pin locked in with sensor facing straight back to firewall. Let's try again fire fire fire bang through intake.

So I'm stumped as bad as I don't want to a strip the front back down to check timing dots. On intake stroke the dots cam face to passenger side crank line up with to passenger side. Crank it around dots line up with each other.

So my question is what am I missing. Sorry for the long post just trying to cover all the bases. Any help is greatly appreciated thanks in advance.