97 2.3 when you started the idle shoots up to about 2200 then drops back down just left the dealership and $100 an hour for Diagnostics they can't find out the problem fuel pressure is fine no vacuum leaks no sensor problem let me hear what you think

 

Idle should "shoot up" on any fuel injected engine on start up, 2,200rpms seem a little high though

Startup goes like this
You turn on the key, computer boots up
First thing computer does is open the IAC(idle air control) Valve all the way, this is good for about 1,800-2,000rpm
Computer also Primes fuel system, runs fuel pump for 2 seconds
Then computer checks Coolant temp, using ECT sensor
You turn the key to START
Engine fires and REVs above 1,500, then starts to drop as computer closes IAC Valve to set "target" idle RPMs
Cold engine target is about 1,100
Warm engine is 700, maybe 800 for automatic trans vehicles

So engine SHOULD rev up every time its started, totally normal for fuel injection

You can Clean IAC Valve, not hard to do, maybe it is sticking a bit so stays open longer than it should


Easy check for vacuum leak
After engine is fully warmed up and idling, Unplug the IAC Valve's 2 wire connector
IAC Valve will close and RPMs should drop to 500 or so, or engine may even Stall, either is GOOD no vacuum leaks

If idle does not drop then there is a leak, and you will need to find it

 

a bad pcv valve will cause a high idle and not throw a code, so if you're not sure of it's history change
it.. they are cheap.