I have a 97 Ram 1500 4wd 318 5.2L 5spd. i just started having a problem were my truck backfires really bad when i start driving it, it runs smooth at idel till i certain point through first gear then starts steadly loosing power and backfiringbad and the whole truck seems to buck and shake, then shift to second its smooth for another 10mph and then starts again, shift to third the samething, fourth and fifth last alittle longer till it happens though. but if you drive it for about 20 to 25 minutes it smooths out almost completely but may backfire if you rev it out in 2nd sometimes. if you park it when its seems to be running fine and let it sit over night it starts the same process over again. what could be causing this? has anyone had a problem like this before? if so what fixed it? i just changed the cap and rotor 3 weeks before this started.

any suggestions would be greatly appreciated,

Chris

 

Sounds like your cat's starting to clog up. Back pressure builds up with increasing RPM's and is relieved when the RPM's drop after a shift.

 

no cats on it all gone, it had the crankshaft position sensor replaced about 3 weeks ago to. the check engine light comes on reading a code 11 no distributor reference signal detected during engine cranking. what else could cause this

Chris

 

any ideas

 

cam sync sensor could be going bad i would start with that...

 

I thought of that but figured i would try to get some more opinions. i'll give it a try anyone else have any ideas.

Thanks, Chris

 

Could be the,map sensor, or an injector that's stuck open. Backfire running on an efi vehicle is likely coming from gas being thrown into the manifold. When you say "runs fine to a certain point", are you saying it runs fine until it warms up a bit? The pcm has probably got youleaning back at idle and heating your manifolds/headers up real good, then when you throw fuel in there at low rpm's it goes right out the exhaust valve and ignites in the exhaust. As the rpms get higher the pcm balances out and the exhaust velocity is higher so you don't get the back fire.You need to put a scanner on it (cheap one - free to use at Autozone, etc.) and look at your fuel trims. Bad coils will do the shutter/ backfire thing, but usually won't run well at high rpms.

 

But as RPM's increase ... he says that power drops off ... and the error code ...[>:][>:][>:]

 

My bad. I missed the code 11 part. Well then I'd say he has a bad cam position sensor. Easy and cheap fix I reckon.