Any ideas on what i can check for

 

When that happened to me, it was low coolant. Not low enough to make the engine run hot, but enough to mess with it I guess; It may have been an air bubble stuck in the system.

My brother had this problem too, but with his truck it was a loose alternator cable.

What have you done to your truck recently?

 

hmm alright, And iv done alot of chassis work like clutch and steering parts and alxes, the valves i adjusted, i ran seafoam through my air impluse thing, changed the fuel and air filter,changed the oil.new cap and rotor, basically a full tune up

 

I would check the coolant there are cooling passages in the throttle body or clean out the throttle body and check the base idle it should be on a sticker on the hood right above the airbox my 22re was doing that/has done that the ecu is trying to relearn the idle but if someone has messed with the idle adjustment it will surge i think the base idle is supposed to be 750 rpms although mine would go below like 850

 

You could try taking off the thermostat housing after everything is cooled off, too. if the coolant isnt high enough to reach the thermostat, pour some in underneath the thermostat then put it back on. Then put the housing back on, and make sure the radiator is full up. Hopefully it isn't a coolant clog anywhere... I mean they make coolant flush kits, but a good clog is tough to get out without really ripping into it. When mine had that stupid idle surge, it was after I had flushed my system and replaced the coolant. I imagine you have checked connectors and what not. You could try disconnecting your battery for a while and reset your ECU, but that may not solve the problem. Make sure your main serpentine belt is nice and tensioned too. I called up my brother and it wasnt his alternator wiring; He replaced the alt but didnt re-tension his belt. From the sounds of it, I would think coolant related. But I suppose it could be anything. Just take your time and run through all of your checks. I was super frustrated when it happened to me. I though I had killed my truck.

 

Alright, well my coolant looks good and looks clean. But the guy who had it befor me did mess with the idle timing and fuel mixture but i had it all set back to normal. Now my air pulse thingy isnt gargleing like it use to, Could that be part of the problem

 

burp the cooling system.. if you dont know how hit up the search function, you should be able to find at least 1 post about it. let us know how it goes..

 

well i only needed to add like a qt to the radiator and that was it