Fast idle after warm up
Asked by GuruWPYTL May 18, 2018 at 07:33 PM about the 2003 Dodge RAM 1500 SLT Quad Cab LB RWD
Question type: Maintenance & Repair
4.7 after a couple minutes warm up it idles up from 1000 to 1500 rpm. I
changed TPS and it made no difference. I was told maybe a vac leek but it
idles fine until it warms up. Help !!
3 Answers
jetjurnigan answered 6 years ago
Your ECM runs in a default mixture mode till the O2 sensors get warm enough. Then they take over. It's possible one of them are bad...but that's a big guess. Do you have access to or can you get your hands on an engine scanner that reads live data? You can get 1 for around $30-50...shop around. You'll find it's one of your best investments if you intend to do any work yourself. Once you've got one, you're looking for long n shjort term fuel trims, O2 sensor reads, intake air temp vs. ambient and coolant temp.