[ChunkFunky]

I guess technicaly you're hearing backfiring through the intake as opposed to the exhaust... but whatever it's called can be caused by a couple of things from way off timing to crappy gas (so I'm told) to any other factor that would effect valve timing in relation to ignition timing. When I first did my heads I had it bad and it was ignition timing.. that was cleared up and all was good.. and then some months later I had what you had, popping durring acceleration and I was told it could be BAD GAS or a lean condition... though I'm sure it could be a number of things.. that's what makes it a pain the arse to diagnose


as for the speedo... ford dealers suck. they are usless, around here at least, see if someone get hunt down the part number from an FMS catalog or something.. and then you can order the part through the dealer as long as you have the par tnumber
-as