2 Questions:



What is the stock vaccum for an RD? When it drops below normal levels, will it throw a code?



My car has been running kinda crappy lately, and getting below average MPG, and I know there are some hoses that could be losing vaccum, but it never throws a code.



Car stumbles occasionally, seems weezy accelerating sometimes, other times pulls strong. I did the fuel filter about 2 months ago, air filter is new, plugs and wires are new, so I'm at a loss.

 

18-22inhg at idle



If you have a vacuum leak and your fuel trims go to far out you will throw a P0171-Bank 1 Lean.



I would try running some injector cleaner through the fuel system and sea foam the sh*t out of the intake. Change your plugs again after doing so. Chep enough to do.



Also check and make sure you don't have any brakes dragging. A caliper hanging up will kill your mpg's

 

If you have low vacuum in the manifold, it's either a vacuum leak or an obstruction in the exhaust... usually a melted cat.

 

put a cup or two of 99% isopropyl alcohol in the tank. It could be water in the gas. Alcohol is cheaper than parts!

 

If you know someone with a vacuum gauge, checking the vacuum is free.