GMC safari 2003 ECT Location

P0401 Is usually either the egr, the port under it is clogged with carbon, Get a steel coathanger and ream it out, all the way thru to thre throttle plate. Then clear the code, if it resets, change the egr position sensor...

[quote:bbcaf6c9f5="trlwridgerunner"]I have a 1998 ford escort and the check engine soon light stays on.I had it scanned and it came up EGR insuffient flow detected and also EGR excessive flow.What could this mean and how serious is the problem? I have 115,ooo miles on it.[/quote:bbcaf6c9f5]

For a start take it out and clean it and also the metering orifice see what happens. Also check the DPFE sensor

I'd say that It's not a clogged passage because you can't get both codes if it were. Most likely a bad DPFE sensor or a remote possibility a sticking EGR valve....