I unplugged the mass air circular switch out and engine still is revving (not missing) just revving between 5000 and 10000 rpm up and down and it does it irregularly like when its cold or hot /at a stop light sometimes and in the garage usually after driving it around. Engine temp is fine/seems to be a tad worse in gas mileage/ a really strong chemical smell halfway between gas exhaust and something chemical. Replace ovp relay a few months ago/ has 188,000 bought it 1 year ago w/ 159,000 miles. The DTC is pulling a code 10 which is the mass air flow issue. HELP