Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

97 Hyundai Evap codes

I just picked up a 97 Hyundai Elantra. Its a bit of a project…its throwing 3 codes… P0442 (Evaporative Emission Control System - small leak detected)

P0455 Also the evap system - no purge flow or large leak

P0303 Engine misfire

I’m guessing a new gas cap might fix the small leak. Do you have any suggestions on the “purge flow” or large leak?

I didn’t notice the engine skipping, but it is running very rich. Perhaps a plug is fouled.


You say that it’s a bit of a project. Do you plan to do this project? If you do, you get the repair manual, read it several times, and then start your project.
When you read the repair manual, you’ll see that there is more to the evaporative emissions control system than a gas cap.
There will be test procedures in the repair manual for the purge flow problem. One does NOT just throw a purge control valve at it in vain hopes that that will fix it.
The engine computer has already diagnosed the problem and told you what it is. It says, that P0303: #3 engine cylinder is misfiring. It might be caused by a spark plug, and/or spark plug wire, and/or the ignition coil, and/or other part(s) of the ignition, or fuel fuel system, or other part of the engine.

I was merely looking for some insight into the problem(s). I realize it is probably more than the gas cap, as it threw out not ONE, but TWO codes. Thanks a bunch…

BTW, are you referring to the FSM, or will a Haynes book suffice?