Hi guys,

My 94 GT has backfires through intake on low rpm's under load (mostly when engine is cold). After inspection of an ignition system, we have discovered spark illuminations around ignition coil on high rpm's. Does it mean that the coil is bad and it may cause backfires on low rpm's? Could also bad spark plugs produce this problem? Factory sparks are Motorcraft with .55 and I have installed Bosch with 0.44.

Before ignition system check, we've also checked computer codes and it says EGR valve is bad, but most people say that this can't create backfires in the intake manifold but instead, it can create backfires in the exhaust system on deceleration.

So I really need your help on this, I need to decide what components I need to buy, well, here's list:

Ignition coil
Spark plugs (factory ones, with 0.55 gap)
Spark plug wires
MAF sensor
Water temp sensor
EGR valve

Thanks to all