Wild Thing Happening ! Backfires !!

[cz777]

well you drive old mj backfires at times .....but starts great etc but only cold at/below 40* outside air temps .....its a ghost - all the values of the temp senors are good ..used ice cubes to test the ohms ..fuel psi and volume are good ...its a TBI  tps is good too ??? ideas over this one ????thxs   

[87manche1]

Specs 2.5?

[MancheKid86]

tbi would be throttle body injection so i thinking its a 2.5,

 

is the back firing happening before tdc or after (after would be in exhaust and before would be through intake)

 

before could be a bunch of things, timing, carbon deposits, fuel mixture, hot spots on spark plugs,

 

if its after in exhaust its from an excessive rich mixture where the after fire or flame propagation still takes effect in the exhaust,

this is likely caused by your egr valve which will dump more fuel in to warm the engine up when in cold temps iirc

[87manche1]

Thats y i asked my expertise is with the 4.0. know hardly anything about 2.5 hope u get it figured out.