1989 Bronco exhaust issue/timing?

[Fist]

Sorry I couldnt find another thread with quite the same issues as mine so here goes. I have A 1989 Bronco 5.0 with the M5R2 trans. Last month I replaced the clutch, ****** and line. Last night I replaced the exhaust manifolds with Pace Setter headers a Flowmaster Y pipe and high flow cat new flowmaster delta 44 and tail pipe. The issue is I backed it out of the garage took it for a test drive and now it the whole truck vibrates in 4th and even worse in 5th! I have no clue why, possibley swapped spark plug wires or something I've no idea. It drove into the grarage beautifully and now it's borderline undrivale any guidance would be appreciated!

 

[Rons beast]

Hey fist, Welcome,

The first thing that comes to mind is one or more plug wires may be hitting the headers.  It was ok till the heat burned the insulation now the wire is grounded and you have a dead miss.

I'm assuming any sensors are still active...

Good Luck 

 

[miesk5]

Yo fist,

As Ron advised and:

besides firing order, routing is aslo a biggie;

Spark Plug Wire Routing TSB 94-04-10 for 87-93 5.0 - engine miss, spark knock, buck/***** surge and other driveability concerns Source: by Ford via Steve

see diagrams as well as:

http://www.supermotors.net/clubs/superford/registry/media/470415