Bought pickup with bad head gasket so i replaced it along with timing chain and new guide,new coolant hoses,deleted egr, and vacuum lines other than vacuum line to fuel pressure regulator and pcv valve ,new plugs,wires,cap,rotor. New alternator, I started out with code for tps sensor ,knock sensor ,02sensor the tps sensor ended up being good my adjusment screw was screwed in to far
​ an my coolant sensor was bad so pickup was stuck in high idle because computer thought pickup hadn't warmed up anyway got that figured out I put a new muffler on cut the cat off to see if it was plugged and installed a 02 simulator from magnum tuning for 02 sensor now no more code for 02 sensor . Knock sensor code still on i replaced knock sensor and pigtail still on so I put old sensor back in and then took stranded copper wire and wrapped it around the outside of my pigtail wire spiraled it up as far as I could get it and taped over the top of it and no more check engine light ,but now I still cant get the pickup to idle right I've searched for vacuum leaks the timing is on 5° and 12 when not jumped anything else I could check ?adjusted valves when i did the head gasket they are in spec .

 

It is an '80's era microprocessor, 8-16 bit CPU running at a very low speed, just what are you expecting out of it?

Your throttle plate adjustment screw should never be touched, either you or a previous owner didn't follow the directions for tps adjustments... Quite normal for us old bastards that are used to a carb adjustment.

You are going to need to provide more details. Engine speed, tire size, final drive gear ratio, throttle position, and transmission...

 

Use an unlit propane torch and run it around fittings while idling, when it smooths out that is your leak. Now you could have a bad TPS too.

I took the expensive route and sent the throttle body out to LCE with a used TPS from Ebay for a 3mm overbore and overhaul. Money well spent, not an issue since; that was not something else. I also put on the larger Celica Supra VAFM, found one in Chicago; at Chicago prices.

 

Thanks for the replies as to the idle screw there wasn't one in it when I got the pickup so I just put a bolt with a nut on it to lock it in place didn't know what to set it at then I got the tps code so I adjusted the tps with ohm meter and had I think if I remember right 85 mm gap between idle screw and stopper and that's where I left it at .but I'm not getting any codes now if the tps sensor was set wrong wouldn't it throw a code ? I did install a tach to see what my idle was atand have adjusted the idle air screw to lower and raise it but it sounds better when it idles close to 1000 rpm . It's a manual pickup single cab short bed 4x4 with 235x75x15 tires just hestiant on hills ,new air filter,new fuel filter and new fuel pump in tank .

 

1000rpm is too fast, should be 500 to 750. You have an air leak somewhere, have you checked the VAFM pipe for cracks on the underside?