I recently had the ignition coil replaced and I changed the plugs and wires afterwards! I hooked the wires up according to the diagram the mechanic gave me but when I started it up it run like crap and backfired! When I switched #5 and #6 wires it stopped backfiring but still runs like crap! Is it possible it ruined plugs or wires! And what is the correct hook up!

 

A little more info on your trucks particulars would have been helpful. Below is for a 4.0 OHV engine.

By the way, Motorcraft or Autolite plugs only, double platinum. No single platinum. The waste park system on the Rangers will "eat" them.

 

My engine is a 3.0 v6 and yes I used double platinum plugs. Now it's showing a code that says mafs sensor has low input! What does that mean?

 

It could be a faulty or dirty MAF sensor. The easiest thing is to get some CRC MAF sensor cleaner and try that first. Do not, I repeat do not touch the MAF sensor wire while cleaning. They are fragile.

You can also unplug the MAF while its running. If it stalls the MAF is working as it should, if it stays running there's likely an issue with the MAF.

Of course, this test is a general rule and not an absolute.