1995 S/C loud noise from head

06-23-2005, 12:11 AM
My previa has been increasingly losing power for about a month. I live in the mountains, the last time I came up, I couldn't get over 20mph on the steep grades, and it was overheating, so I stopped many times. When I did get to 30mph in 1st gear an extremely loud noise came from the head area, like a piston running into the valves. At 4000 feet elevation, my compression is 140, 120, 140, 140. I removed the valve cover and everything looks ok. I pushed on each of the valve springs and they appeared to have the same pressure. Previously I had 3 codes, (302,402,420) I replaced the EGR temp sensor, the codes were cleared, I have only driven it about 20 minutes since. I had thought I might have a collapsed converter causing my power loss, but I can't relate it to the noise. Please help. It has 200k miles on it.

07-03-2005, 12:59 AM
Did you check the timing?
Air filter?
Spark plugs? (Are you running rich or lean?)
Oil and coolant level?

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