85 GT running rich? (Page 3/3) Patrick JAN 20, 05:55 PM quote Originally posted by fierofool: Usually, a defective EGR valve will cause a high idle. About the only defect they can have is a leaky diaphragm or gasket. There's always an exception to the rule. quote Originally posted by Patrick in This Thread: I got in my trusty '88 Formula this morning, started it up... and the engine sounded like it was running on somewhat less than six cylinders. It was very rough. I was quite puzzled as the car has always run so well. I turned off the engine, opened the decklid, and looked around. There didn't appear to be anything visually wrong. So I left the decklid open, started the engine again, and went to have another look. And then I noticed something really weird. It's probably the original EGR valve on this 2.8 engine... and it was looking mighty strange. I didn't take a picture of it on the car, but the picture below is what the EGR valve was looking like while the engine was running. There appear to be three rivets that hold everything together, and anyway... all three rivets had let go, probably due to 30 years worth of corrosion. (EDIT - I just noticed in my image below that two of the rivets had probably rusted away long ago, and the last one finally let go.) So while the engine was running, the pressure of the exhaust was pushing the entire diaphragm housing of the EGR valve up as far as can be seen in the image below. The end result was that the engine was struggling to run with the EGR valve wide open. I pulled the EGR valve off a GT parts car here, and the Formula is now happily purring again. fierofool JAN 20, 09:36 PM Wow! I've never seen anything like that before.