Saturn SES p0172, 0300, 0507

Saturn 2002 SL1 5-speed. My SES light has been on constantly for about a year (was intermittent before that) with the codes P0172, P0300 and P0507. The car also idle high (2500+) occasionally at stops. My mechanic said it is likely an intake gasket but would need a full diagnostic to determine and that is not a safety hazard to drive but that I am getting less mph. I can’t afford to fix it now but I have an emission test due. Is there a way to turn to light in the mean time? And other cheap things I can do to help my mileage like gum-out.Thanks

You can turn off the light anytime you want with a code reader/scanner. People at auto parts stores will read the codes and then clear them (turn off the light) for free. But its not going to help. You can’t pass the emissions inspection that way. After the codes are cleared the system will take a while to be test ready again and by the time it is your codes will be back.

Intake gasket is a reasonable possibility, but it doesn’t take all that much in terms of diagnostics. Most any decent mechanic - even a shadetree type - can tell you whether its the intake withing about 15-30 minutes with a can of carb cleaner or unlit propane torch or something of that nature. What those codes & symptoms point to is a fairly bad vacuum leak. It could be the intake or it could be about $1 worth of vacuum line. Find someone who isn’t going to tell you that finding a vacuum leak is rocket science.

Nothing is going to help the fuel economy other than normal things like tire pressure, alignment, healthy cooling system, failure to pretend you’re on the Indianapolis Speedway - stuff like that.