High Idle issue...
Hello Guys this is both my introduction and why I looked for this site...
I have a 2000 Ranger 3.0 flex, 5 speed, 4x4, super cab with 180.000 +miles.
Ok so my fuel mileage when I bought the truck was always around 19 mpg. (I always check my fuel mileage at every fill up) kinda anal that way. A while ago my mileage started to drop... SO I did a full tune up. Plugs, wires, fuel filter, air filiter, O2 sensors.... bla bla bla... Still my fuel mileage has continued to drop I was getting as low as 14-15mpg highway. I have been very confused by this... I burn about 1/4 quart of oil per 3000 miles... I use Amsoil full synthetic 25,000 mile oil and Change the 25000 mile filter every 7500 miles. I had the oil tested at 20,000 miles and it still tested well so I run it to 25,000 miles.
Last week I read on this site about Cleaning the MAF sensor, I have cleaned the Throttle body about every 30,000 miles. SO I cleaned the MAF, throttle body, and IAC last week. That is when I started having a strange high Idle issue. Ended up replacing the IAC... thinking it must not be working right.
When I start the truck it goes through the warm up cycle just fine... then goes down to normal Idle which looks like 900 RPM on the tach. But on my OBD II reader it shows as 750. once I rev up the motor for any reason (Driving or just blip the throttle) it idles at 1350 for about 2 minutes before it again drops to 750 where it has always Idled before. i have used my OBD II reader to log and watch what is happening with my MAF, TP sensor and Load% in real time. Nothing seems inconsistent. Or like the #'s are out of the normal range. I have checked for vacuum leaks. I cant find any. I am not getting any codes. Other wise the truck is running great again and I got almost 19mpg on winter Gas I did not even get that one time this summer on summer Gas!!!
Oh and I did use the search function I am a newbie to this forum but Have been a member of some other forums for years.
Last edited by Tigdim; 10-28-2010 at 07:41 PM.