Isuzu Repair: 95 Rodeo gas milage, egr valve, gas milage

Question
I have a 1995 Rodeo and when I bought it 1 year ago it would get about 22 mpg. Now it is down to 12, I have done the plugs, filter, and change my oil every 3,000 miles, in the last 3 or 4 months it has dropped down to about 10 mpg and my exhaust really stinks, I mean it is really bad. What else could i check or do? Thanks

Answer
Well I bet you have a clogged egr valve, clogged exhaust. You could have extremely low compression or bad rings. I would start by cleaning out your egr valve(and dont use carb cleaner!, small steel or wire brush will do fine.) I would also check into an evap system problem.