Hey There, I have a 1994 Ram 1500 5.2L when it is cold outside and I start the truck it idles rough and hesitates but does not stall if I drive it after starting it bogs down upon acceleration and it back fires, when the engine warms up it runs great. When the temp outside is warm the truck has no issues. The battery is putting out over 14amps and I changed the upstream O2 sensor there is no downstream O2 sensor never had one. Please help me
Thanks
Scott

 

What temp does the PCM think the engine is at cold start? (need a scanner for that one.....) Any codes?

Welcome to DF!

 

Thanks for the reply
the outsidetemp is cold between 25-40 no warning lights are on

 

Yeah, but what temp does the PCM think it is? Coolant temp sensor has quite a few failure modes that won't set a code.....

 

Today st 310pm left work truck ran with no issues. So what do you think is the problem

 

The intermittent ones are always the most fun. You are likely going to have to do some data logging, in order to see what is going wonky when it doesn't want to run right.

 

This morning temperature here 27 and it really acted up I would say major hesitation when in drive and accelerating. When I'm accelerating it's like bogging down and you can hear it backfiring then as it got warmer the engine started running fine with no problems. It's very frustrating I need some pinpoint help here

 

You need to find out what various sensors are reporting when the engine is cold, and what changes as it warms up. There are several sensors that could cause you issues, as could slightly low fuel pressure.

How long does it need to run before it straightens out?

 

Thanks for the reply and to help so far I'm showing no codes being a 94 Dodge truck it's OBD one I don't have a scanner it maybe less I half a mile to a mile before it starts to run right it never stalls. Right now I am leaving work it's running fine temperature out here is about 38° On an OBD one how do you get it to show codes is there a way to turn the key numerous times to get the check engine light to flash stuff

 

I think if you cycle the key three times, (but, not start it) it will flash codes with the CEL. But, if it isn't on... you may only get a code 12.

It starts running better about the time the PCM starts paying attention to the O2 sensor... so, could be low fuel pressure, (easy to check, parts store should have the gauge you can borrow) or maybe IAT sensor.....