Missing EAR diagram and hoses

erratic up and down idle is usually either a faulty idle air control valve, located on throttle body, or vacuum leak.

Check vacuum hoses by spraying each one with carb cleaner while engine is idling. If idle smooths out when one is sprayed, then replace that vacuum hose.

If all are ok, then the IAC valve is bad. This is replaceable by itself. But before replacing it, try pulling it and cleaning the ports out of any carbon deposits

It runs about $144.

ok more info... good.
ok , compression is #1 , no amount of spark or fuel makes a dead engine good. (the 120 is low x4 but i bet you didnt do it WOT like the
instructions stated. most cars can do 150 easy. , all my 1.6L do 180.
the reason i ask is the cam belt slips after 50miles and all 4 jugs
drop from 180 to 120 or lower. so did you block the throttle open.
my wild guess is compression really is good and the belt never slipped. yet. (interference engine they are) all of them
so backup and read my post, did you check spark yet.

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Check connections for throttle positioning sensor if there in good cond. replace sensor

HI Joneydaniel

Check for a vaccum hoses or tube broken off manifold it may have gotten brittle, Listen for air suction in and around engine bay or where all rubber hoses are connected you can use a 4 feet of rubber tube hold one end to your ear and other move around in the engine bay becarful of fan and belts and pulleys while running allways have somone with you at all times.The other posiability is your throttle position, return spring weak or even throttle position switch that is defective,, its good time to bring this car to the dealer you dont want a run away car in your hands and you would be responsiable for any accidents your insurance company wouldnt like that. Its nice to share the easy things to look at but really its how far to take on a project like this and where trouble shooting takes us,

Joe

take the head off bent valves thats for sure

Throttle position sensor, check this out. Also try cleaning the throttle body with throttle body cleaner may be all it needs'

The single wire sensor for the gauge is located in the engine block directly below the #4 exhaust port.

If its a 99 4 cyl 2.4 ltr it should have a timing chain. Check your PCV (positive Crankcase Ventilation) Valve. it should rattle when you shake it. sometimes you can clean it with carb cleaner. but for what they cost, just go buy a new one. When they plug up it doesn't let your crankcase breathe and you will start getting oil in your throttle body or carb. Gas engines don't like to run on oil for the combustion process.4 cyl engines dont have a pcv valve just the v6 motor...

i have came across simler problems in the past so im going to give you a list of four main suspects number 1; a broken or pereshed vacuum hose at the trottle body or inlet manifold.2 a blocked injector 3 a fuel injection system fault 4 a disconnected /leaking or perished crankcase ventilation hose.Before you try any of these by a can of fuel cleaner and run it through your system remember a small piece of dirt half the size of grain of salt is enough to cause this problem good luck.adrian

Matter not whether plug fires out of engine. Put it back in and clamp a timing ligh to it. If the light won't fire, you don't have enough spark to fire cylinder, hense miss.