94' backfiring upon acceleration

[lwillits]

My 94 EB 4x4 was running fine but it was time for a Tune up (114500). I went to AutoZone.com (living in England right now) and ordered new motorcraft plugs and wires, air filter, fuel filter and pcv valve. Installed all but the plugs, cause they sent me the wrong ones. I Reinstalled the old plugs with the new wires. Started it up and it ran, but with a Miss. Took it for a test drive and it backfires when ever i give it acceleration. It is coming from the engine not the exhaust.

Triple checked the wire placement. - nothing

put the old wires back on - runs a bit better, fine at idle and low speeds backfires on acceleration

Checked for vacuum leaks and replaced 2 vacuum hoses, still no improvement.

Going to clean the MAF tomorrow, prob. gonna reorder new spark plugs tomorrow too.
What am i doing wrong...? Anyhelp would be greatly appreciated.
CHEERS MATE..

 

[trollkepr]

You are right calling it back firing. When it goes out the exhaust it is technically called after firing. hehehe

Now your problem. I would betcha that you have a crossed wire. It can be easy to overlook. Go with the beliefe that there is something wrong with the wiring and keep searching. I bet you will find it.

 

[urbanistic]

Sounds to me like a wire mix-up.