can a missing gas cap make a car run bad?

Answer 1

Creates a back pressure in the fuel delivery system on the car.
Also responsible for many Check Engine lights on the dashboard.

Answer 2

No it will not make it run bad. It will turn on a check engine light but the car will run fine. If your car has the system on it what it does is check the evaporator system. That system takes the un burned fuel vapor and puts it back in the gas tank. If the gas cap is not there it sense a vacuum leak and turns the light on. However it does not affect the way the car runs at all.

Answer 3

it depends on the car, but having a missing gas cap, means that contaminants will find it easier to find their way into the fuel system

some cars will run badly with a missing gas cap, but most will be OK

Answer 4

Yes...Especially on some of the newer stuff. Ex...Honda uses a pressurized fuel system and will run terrible if the cap isn't tight.

Answer 5

Well it can but not that bad. It kills ur Gas mileage somewhat because of fuel pressure lost. Gas caps are cheap so go but one at an auto parts store for like 5.00$

Answer 6

A missing gas cap will not affect the cars performance at all. However, you need a gas cap to prevent vapors from escaping into the environment and causing pollution. You also need to worry about a fire hazard.

Answer 7

Oh, YES! That's actually the number one cause of the dreaded "check engine" light. Either missing or not sealing.

Answer 8

yes. stuff a rag down into there until you can get a replacement.

see http://www.carcare.org/Emission_Control/gas_cap.shtml for more info.