How many miles or km on this car?

This is now a 17 yo car. Rubber parts are hardened and brittle and prone to cracking. That small leak could be the gas cap. Inspect the gasket and the rim of the filler for dirt corrosion and other defects.

How old are the spark plugs? If you don't know take them out and inspect them.
I guess this car has coil packs and plug wires. There is a good chance they are burnt out or cracked and leaking voltage. In the dark run the engine and spray water on the plug wires. If you see any sparks replace all wires.

Report back.

 

There's one other thing you should know. I had to do MY OWN research to discover this when my own car WOULD NOT RUN RIGHT, and the Hyundai garage could not figure it out. The intake manifold on these little 1.6 liter engines (maybe the 1.5's also??? but not sure) is prone to developing leaks. Mine started leaking at cylinder #1. I sprayed throttle body choke and carb cleaner against the mating surfaces, and it sucked in so much that it started stumbling and faltering like it was gonna stall out altogether. I smeared a massive wad of silicone against the entire area where manifold mates to the head, and it solved my problem.

 

Hmmm. Maybe the "Manifold Absolute Pressure Low" is related to that? Silicone may work alright. I'd prefer replacing the intake manifold gasket.

 

Replacing the gasket would be the best and correct way to go, IF you actually do have a leak. I personally didn't want to spend the money, and didn't have the energy, enthusiasm, motivation, or time to pursue it, so just "slathered" it with high-temp silicone RTV. Don't spend the money unless and until you know for sure you have a leak.

 

Hey Guys,
I learn something new almost every day and this is a first for repairing a leaking manifold gasket.

I guess there is something to the saying, " Necessity is the mother of invention" , because it sure is shown here, lol.

 

I had a number three cylinder misfire on my 2001 Elantra. And it turned out to be the in-take manifold gasket.
Took me three hours to replace. The gasket was less than twenty dollars.
The toughest part was reaching around to get to the bolts holding the in-take manifold to the engine.
Unexpected was the bars holding the manifold from underneath. Tight bolts.
When done, was so happy to have fixed it. Then noticed the rear cross member was so rusted that it would fall apart when touched.
I gave up and junked the Elantra. The joys of living in the rust belt.
Oh, it also had an evap code which I never figured out.

 

Hey avisitor, I also have an incorrigible Evap Emmissions code. As I had previously stated, this has been a pretty reliable car overall (my '04 Accent). But one of the frustrating problems I've been having besides the rust is electrical problems. A "new" electrical problem arises about once a year on average, but until recently was not a crippling issue, just a nuisance. But, now I have an electrical issue that is causing the computer to exhibit bogus codes. The one code that has been present for several years now is the code for the Evap Emm module. That module has been checked out REPEATEDLY, and it is indeed functioning properly, no malfunction at all. But the code can't be deleted because the computer is getting corrupted by the electrical malfunction. I've had to get the "Waiver" for the last 2 inspections so that I could continue driving the car "legally". I know I could find and repair the problem myself, but, if the issue is under the dash, I'm not going to pursue it. I HATE working under dashboards!

 

So, you have a confirmed issue with the evaporation emissions module?
My issue was a small leak somewhere. Tried the tightening the gas cap and replacing it.
Tried replacing purge valve twice due to recommendation of mechanic.
I just gave up.

 

There is actually nothing at all wrong with the evap emiss module. This has been confirmed repeatedly. It is the blasted COMPUTER that is in error. BLEEPING THING! So, like you, I just gave up. No time or patience to isolate and repair the electrical problem that is "confusing" the computer.