:banghead: i have just replaced cam in jeep. now it is starting hard. starts to backfire at aprox. 1300 rpms. it idles great but once rpms go up, backfiring starts. oh its a 4.0.

I would double check your timing marks.

Another thing to check if the distribitor is set right.You cannot do it with a timing light which the timing is not adjustable.There is a hole you stick in a small pin,screwdriver or anything small

whare is this hole located and what is its purpose? ok found the hole and mark is on. ok i just got done pissing with this thing again for another 3 hours. i checked double checked triple checked and quadruple checked timming marks. marks are on, distibutor is on. last nite i had it idling but tonight i cant even get it to pop off. i know al marks are on but still not running please help before i pour gas on it and throw a match on it.

If you checked the distributor when the timing marks were lined up I would check the plug wires with a wiring diagram its easy to install them on the wrong plug.

hey just so everyone knows i found the problem. the cam that i got had the pin 180 deg off. i turned the cam with the gears off 180 deg. set the distributor (a couple of times) and it was running like new. the time i had it running at idle i just had the distributor off by one cogg. THANK YOU EVERYONE FOR HELPING ME OUT. now i dont have to burn it. THANK YOU

Now all you need is a scan tool to fine tune (sync) your fuel injection timing.

hey just so everyone knows i found the problem. the cam that i got had the pin 180 deg off. i turned the cam with the gears off 180 deg. set the distributor (a couple of times) and it was running like new. the time i had it running at idle i just had the distributor off by one cogg. THANK YOU EVERYONE FOR HELPING ME OUT. now i dont have to burn it. THANK YOU