Here's one I could use some help on. I have an 89 RS Camaro with the 2.8 TPI motor. I'm the second owner of this car. I've done a lot of little things to it to try and get it ruinning right and it's continuing to get closer. (Full tune ups, plugs,wires, cap,rotor,oil/fuel/air/tranny filters, flushes, new TPS, IAC, MAF, Water Temp, sensors and Thermostat) Each has gotten more performance back out of the old girl. But it still has a problem with the idle being off at times. It usually idles at 650-700 at a stop in gear. But it'll bounce to 1200-1500 at times and then is slow like it's missing a cylinder all together until 3500 rpm's. Even while cruising, if I let off and get back on it lightly, it'll do the same thing start to sputter and run rough, want to stall if I slow down to stop. It's not an all the time thing. Maybe once in a day, and not even everyday. I changed out the PCV valve and am looking at the EGR next (as the PCV was black, clogged and wouldn't close). But I went to replace the MAP sensor as the vacum line to it had broken a month ago. I fixed the line immediately, but figured replacing the thing couldn't hurt. But the part they gave me at the shop, had only 3 wire ports hor the wire harness that goes to it. The one on my engine has 4?!?!?!?! Is it from a different year? The guy at AutoZone was as baffled as me on this one.. Help please. I know the 2.8 isn't much, but I need it to run good enough for a few more months until I slide the 3.8 turbo with 200 tranny and 3.42 rear end into it. Plus it's no fun getting passed by and the engine dies if you go to get on it.