Vacuum leak or replace Part?

Hi All,

I have a 1999 Rodeo 3.2l DOHC and sometimes it idles high. I have tried the usual remedies (IMG replacement, etc.). Today I unplugged a few sensors one at a time to see if any one sensor was causing the problem. I assume this is how you might find out which sensor may cause the problem. Anyway, I unplugged a sensor and the idle eventually came down. I'm not sure if it is the 'vacuum regulator valve' or, according to myisuzuparts.com, the 'Vac Cont Solenoid'. It's located on the front of the engine just below the TPS. I plugged it back in and the idle continued to be low. I noticed two vacuum lines nearby appeared to be in good shape but one, wrapped with a spiraling plastic cover, did not attach to the throttle body with a clip and was easily moved about. That made me think there was a vacuum leak there. Should it have a clip? what is this part? how can I test it?

Also, I was getting a CEL and came up with codes 0342, 0341, 0122, 0102, and 1133. As far as the first two, I am waiting on a new timing belt kit as I am at 117,500 on original belt. 0122 relates to the TPS, which I unplugged and plugged back in, probably causing the code, I also disconnected and re-connected the MAF, which may have caused the 0102. I replaced the drivers side pre-cat oxygen sensor last fall (Bosch), but I get this code intermittently - I get a CEL for a day or two and then go a few days with no CEL. This code can be caused by a vacuum leak, though.

So, do I need to replace and secure vacuum lines (how do you know what size to get?) or do I need to clean or replace the part under the TPS?

thanks