Hello, new to forum. I have a '97 monte carlo LS. trying to resolve a problem with high idle, also will not shift from 1st gear without warming up about 10 minutes. Car has 116,000 miles. Wondering if the most common problems could be IAC, TPS, O2 sensor? Thanks for any help.

 

sounds like the cats clogged, let it run and check the cat to see if its red hot, thats what id start with

 

The cat doesnt necessarily have to be red hot to be clogged. It does sound like a clogged cat though.

 

first i would get a diognostic done first to help to nerow it down it could be a few sensors/ but do a simple things first to do to nerrow it down as in a tune up and new wires. but it sounds like a idle air controll valve that is a culprit but replace the plugs and do a computer scan at a shop you know they will show some codes some where. i dont want you to do a blind shoot replacing things that dont need to be changed. befor there time idle air controll valve and a dirty mass air flow meeter can also do a bad shift. when my mass air flow meter went bad i was getting bad shifts. but with the high idle i would deffenetly get a diognostic done. it is cheaper than to replace all the sensors and the cat

 

just a way to tell if it is tho, or at least could tell its bad

 

Thanks for the replies. I changed the plugs this past weekend, but haven't changed the wires or checked diagnostics yet. Is the diagnostic check worthwhile at the local autozone, advanced auto, etc?