Rough Idle when warmed up?

DANNYROBINSON

MEMBER
2004 FORD RANGER
140 MILES

My Ford Ranger Edge (2004, 2WD, Automatic Transmission, 3.0 V6) has been idling rough once it reaches normal operating temperatures. I've installed new sparkplugs, new sparkplug wires, new ignition coil, new Idle Air Control Valve and cleaned the MAF sensor. Unfortunately none of these has had any effect on the condition. I've ordered a new PCV valve from O'Reily Auto Parts (Advanced Auto didn't carry and couldn't order the part). Any questions and/or suggestions relevant to this problem would be welcome. Thanks!

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1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

There are a couple things we need to check. First and foremost is to make sure there are no codes. Here is a guide that helps with this:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Next is to check for vacuum leaks. I am pretty sure this is going to be your issue so here is a guide that will help with that:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

The last possible cause since this seems to happen after it is warm is a possible o2 sensor issue. Basically the o2 sensors are ignored until the engine warms up. So once it is warm if it is running rough then the o2 sensor could be giving faulty information. Here is a test that will help with this:

https://www.2carpros.com/articles/how-to-test-an-oxygen-sensor-02-sensor

Let us know what you find. Thanks