I'm hoping someone could help me here. I've got a 2001 Ranger with a 3.0 engine. When I crank it up, it runs nice and smooth, but when it gets up to operating temperature it starts to idle rough. Cruising down the road it runs fine, but if I floor it, it starts sputtering bad and I get the flashing check engine light. Once I slow down, the light goes off. I've recently replaced the plugs, wires, and coil pack. I've also cleaned the MAS.

 

what ECU code do you have

 

You need to check and see if it has any pending or active trouble codes. Most auto parts places will do this for you at no charge. Did this problem prompt you to change the plugs, wires, and coil pack or did this problem surface after the fact? If after the fact, verify you installed the plug wires correctly in the proper order. People frequently get #5 and #6 in the wrong order. Which plugs? Gapped correctly? It would really help if you could get the codes if there are any. A lot of things can cause these symptoms.

 

I don't have a code. The check engine light is not on. This problem cropped up after changing those out.

A little while ago, I went out. At a red light, it was idling very rough; a few minutes later at another stop it was idling smooth, and then at the next red light it was idling with a very minor miss.

 

When I changed out the parts, I did them one at a time, so as the wire was taken off of the old pack it was placed on the new pack before going to the next one.