My daughter has a 2013 Dodge Dart Rallye 2.0L automatic. The vehicle has no codes stored and runs rough in open loop on colder starts.... say the first start of the day. It almost seems to be pinging. I cleaned her throttle body and intake temp sensor. I can't hook up to it to read live data as my scan tool is not updated. I thought maybe there was a TSB and that the dealers reprogrammed these? It seems to be that only when the PCM is in open loop it's an issue. I think she has about 80K miles. I added injector cleaner and topped off her tank with high grade fuel. I told her to only run premium, she has not seen improvement yet. Any info/help is appreciated. Thanks

EDIT: Just an FYI I had her take it to the local dealer, she told them I am a Tech, and there were no codes, it only acts up cold and I wanted it reflashed. So they diagnosed it and told her there are no codes (she told them that) and that they want to install new motor mounts for $1000, she can bring it back if that does not fix it.

I have taken it to a friend and his snap on Modis showed nothing stored or pending. I'm thinking that the computer may need to be reflashed (or it's a bad PCM?), from what she describes it only acts up in open loop.

Maybe something in it's preset parameters is amiss and it does not compensate for something. The PCM should flag any reading out of spec from any component. I was hoping that this might be common enough that others here could help direct me. Thanks

The first thing I would do is clean the throttle body and do a reset on the PCM. Disconnect the positive battery cable then ground the positive cable end for 30 seconds and restart. It may stall the first time you crank it after that. Simply cycle the key and restart it.

It may have a thermostat stuck partially open which would lead to a long warm up time. This causes the PCM to add more fuel, over time it ends up being to rich causing the rough running until the O2 takes over.

Thanks Guitar Jones I will try to re-clean the throttle body and then do a reset. I'll check the thermostat too.

Stat would likely ( but not always - in diag there is no always) set a P0128 ; you cleaned the T.B. , but no idle relearn, but she drove enough since for it to pick up on it. Suggesting premium was a bad idea. Car doesnt require premium, and when you start the car , first thing it does is wing the timing until it hears spark knock. GM and chrysler both had tsb's for that. Those things being said , i have no answer , but due to the nature , i wonder about cam phasers (potentially cold phaser knock before oil pressure builds) or even simple stuff like shield rattle, due to the described condition being cold start , and sounds like before actually out on the road. never had a spark knock at idle or out of gear, even on the worst sucked magum lower plenum gaskets that had let the engine coke itself up full of crankcase oil . even those cases only had preignition under load.