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Make: Dodge Durango
engine size: 5.9L
Year: 2002
Engine searches for an idle speed at temperatures around 20F. It will surge up to 1500rpms, drops to around 1000rpms and does this for 3-4 minutes. Does it wether the defrost is on or off. Does it in park. I don't dare move it until it "warms up" for 3-4 minutes. I have done the following: cleaned throttle plate, cleaned idle speed motor on throttle body, tuned it up, it has a Mopar rebuilt transmission with less than 1500 miles on it. It did it before the transmission was replaced, but has not always done it. The mileage is roughly 79,000miles on the vehicle. The transmission was replaced because it was causing a mock engine miss. The engine never misfired but dealer figured the transmission was causing the problem. It cured the mock engine miss.

J, First, I'd like to thank

Submitted by drivability on Tue, 11/15/2011 - 20:58.

First, I'd like to thank you for your detailed description. If you look at other posts you will see that it is often like pulling teeth to get any info.

Check for:

Trouble codes. Autozone will check them for free. Please ignore them if they tell you the engine light has to be on to check for codes.

Vacuum leaks. Keep in mind that certain leaks will get better as the engine warms up and the molecules expand.

TPS (throttle position sensor) operation. It is a very common problem on this vehicle and can cause it to "hunt" for an idle.

Temp sensor issues. Perform a "cold soak test" and check the output of the ACT (air charge temp) and CTS (coolant temp sensor).

Post back here with your findings or if you have questions on performing these tests. Thanks.

j, In addition to what's been

Submitted by Big Block 409 on Wed, 11/16/2011 - 04:11.

In addition to what's been posted already it's more than likely a CTS problem, but don't go and just replace the CTS like that. Test it first. If you need help with the testing part then let us know. I I know you're gonna get tempted to just change everything and start throwin parts at this problem till it's fixed, but don't do it. All you're gonna be doin is wastin your time and money. Another thing to try is good gas. Don't use cheap gas, because it causes all kinds of problems. Use a Top Tier fuel. Also, if the fuel filter hasn't been replaced recently then replace it now. You should also try several applications of Sea-Foam.