91 with about 220k
blown head gasket 3 weeks prior. used new bar's block seal and seems to be working, that is no mixing of the fluids.
recently, engine surges and fades while driving and now more pronounced. when starting cold it races away and never slows down to normal idle. after a few minutes, it begins the surging up and down though never completely off though I have to shut the engine off. plasticky smell as well. can't really use the truck this way.
what I have done:
no error codes
changed the mass air about 9 months ago
changed out the tps with a new one. same difference so I returned it
cleaned throttle body as best I can onboard
cleaned thermostat and auxillary air valve and small hoses to idle air controller
cannot get an idle air controller to test out at this moment from autozone. maybe will explore another big chain
will explore adjusting idle screw.
any ideas greatly appreciated

 

Check for vacuum leaks all around.

You might as well dive in and replace the headgasket with a good one rather than just a remedy. That way you can be sure what the symptons are.

 

{solved}
thanks to you all especially trainwreckinseattle for his advice re:the idle screw or should I say screw up. my 22re was fast idling and surging and I tried all kinds of tps, etc stuff but the idle screw did the trick. thanks again or maybe not since now I have to go back to work.

 

I wouldnt trust that stop leak. Hell, I wouldnt have even used it. I HAVE used it in the past. Just made a mess when I needed to change the radiator.

Honestly, it sounds like the head gasket is still leaking. I didnt get mixing of the fluids when the hg in my 4runner went. Just smoke, overheating, no heat, and weird idle issues like you describe.