Intermittent High Idle

[tbsexp]

The 98 I just bought has a new problem. Most of the time when warmed up it is idling around 1500-2000 rpms. The truck runs and drives normally otherwise, no detectable misfire , rough running, or trans issues. If someone could point me at what to look at it would be great.

My scangauge pulled these codes tonight , P3800 ,, C1016, P0141 .

 

[pimtool]

Most of the time when you have a high idle its a vacuum leak. Thats were I would start.
Not sure what the code numbers mean. I think the p0141 is a evap code, but not sure.

 

[Lane24]

Have tried cleaning your MAF? My CEL used to always come on whenever I got onto the highway with Oxygen sensor codes until I started cleaning the MAF regularily... the MAF sensor, will get contaminated with debris causing all sorts of incorrect readings.

If you are unsure of what this is or how to do it.. check here http://www.expeditionforum.com/showthread.php?t=4926
There is a really great write up on the little elbow at the back of your vacuum line that causes tons of problems, and on the second page, there is a 'how to clean your MAF 'post. The guy who wrote it up is a freakin genius.... and really good looking, and smart and I could go on and on.... lol.

If those don't help then check back. the P0141 a Sensor Heater Circuit Malfunction (Bank 1, Sensor 2) And I have not heard of the C1016 code of which you speak but there is a P0161-> 02 Sensor Heater Circuit Malfunction (Bank 2, Sensor 2). Which is similar, and P3800 is a new one to me as well.... Never heard of it...
But I'd be willing to bet on the elbow or the MAF.....

Let us know... someone will be able to help if these things don't.

 

[tbsexp]

i'd never seen my scangauge display those 2 weird codes before , i will check/replace that elbow and clean the maf tomorrow , discon the battery for a bit , and see what happens , thanks for the info !