EVAP leak drivability issues?

[moparmaniac07]

My DD '98 Sebring has been throwing an EVAP leak code for a few months now. The engine has also been running not quite right at low speeds, like under 15 mph with very light throttle for longer, kind of surging, like a vacuum leak. I assumed this was the EGR valve going and I just didn't feel like replacing it yet because the car still runs fine everywhere else but my driveway or a parking lot.

Lately the 'surging' has been creeping up in the RPM range. I've been reading that the EVAP leak won't cause driveability issues, but I've also been getting crap fuel mileage. The first tank I figured it was a combination of short trips and cold weather, but the fuel mileage has been getting consistently worse, and this last tank was mostly highway miles.

I suspect the poor fuel mileage may be related to the engine 'surging', or it could be related to a recent exhaust leak if it's before the O2 sensor, or it could just be from really crappy gas, I don't know.
Would the EVAP leak cause the 'surging' and drop in fuel economy? Is the EGR valve part of the EVAP system? Would the exhaust leak cause these problems (it's kind of big)?

No hurry to figure it out, I just had time today and thought I'd try to figure it out.

[min301]

As far as the surging...I'd lean toward a vacuum leak. No the EGR and EVAP systems are not related,
and the exhaust leak...though it could cause drivability issues, you may find that whatever is causing
the surging is likely your whole issue.

Check engine light on? Codes?
Let us know...

[moparmaniac07]

p0442 EVAP leak (small). I know when EGR valves went on other vehicles it didn't show any codes. Would a vacuum leak cause poor fuel economy too? I guess if the EVAP leak uses vacuum, that could be the cause of the light. Are there any ways to check without doing a smoke test? I probably don't have the equipment to do a smoke test.

Edit: New code: p0455 EVAP something or other (I forgot by the time I got back inside) blocked.

side note: My dad's new scanner is pretty cool, it gives more than just codes like coolant temp., rpm, speed, MAP pressure, IAT temp, ign. advance, etc. I'm going to have to play with the new scanner some more.

[wrenchn2]

Vac leak is high on my list also since it is not running right. Evap has to do with handling fumes from fuel tank. EGR has to do with letting some metered exhaust into the intake to cut down on emissions. A piece of carbon holding the egr valve open will also act like a vac leak. You may want to check tsb 609988.

wrenchn2

[moparmaniac07]

Worked on it a little on Sunday while I was changing my oil. Fixed the 4 different exhaust leaks, and blocked off both of the vacuum hoses (wasn't sure which one was which) coming from the purge valve. It seems to not be surging as much (could possibly be my unsteady foot trying to replicate the conditions), there could still be a small leak if I didn't seal the hoses well enough. It also seems like I have my fuel mileage back. I didn't calculate it for this tank because I didn't fill up yet, but the needle is where I would expect it to be after a 240 mile trip yesterday.