Thanks in advance for your help. I have a 1991 Tercel 1.5L, 5 speed manual with 208K miles. It has been having a problem lately getting a nice idle speed. I have cleaned the throttle body, changed and gapped the plugs, changed the oil and checked the PCV valve (it works, rattles when shaken and has vacuum). I do have what I believe to be a crack in the exhaust manifold. The car will stall when the electric fan kicks in. I have adjusted the idle higher to prevent this but, I feel it revs too high. The PCV valve is loose from the valve cover so, I have ordered a new grommet. I am going to try the Seafoam that was talked about in another post. Also, my mileage has dropped significantly in the last few weeks (from around 30 mpg around town to just about 22mpg). Any other ideas would be appreciated. The car runs well otherwise. Also, if anyone has an idea where I can pick up an exhaust manifold inexpensively, I would love to hear from you.