I have a 1989 Toyota pickup truck, 22R 4 cylinder with a 2 barrel carb. and manual transmission. It currently has about 215k miles on it. At 160k the engine was torn down and looked really good so no major changes were made. The problem I?m having is the engine idles really hard, sometimes it shakes pretty violently. I checked the vacuum lines, ignition timing, air filter, pcv valve, thermostatic air cleaner, and sprayed the carb with cleaner. I took off the old egr valve (which was clogged with carbon) and replaced it. I then set the idle speed to the specified 700 rpm. The problem is the engine still bounces around and the engine speed goes up and down between 600 ? 800 rpm, sometimes jumping as much as 60 rpm at a time. When the engine first starts up it runs ok, but once the fast idle cam disengages it runs rough and lopes. When I accelerate it runs ok and does so even for a few seconds after I let off the gas but then it runs rough and lopes. Does anyone have any idea what the problem is?