1996 Escort - OBD-II code: P0440

Try clearing the codes before you drop the vehicle off, just hope that the light doesn't come back on when you pull in!

But seriously, it could be anything evap related between the fuel tank and the canister purge valve. For starters...a loose gas cap, bad fuel pump seal, broken evap line, charcoal canister, malfunctioning purge solenoid, broken vacuum line to the purge solenoid and maybe some other things.

Probably have a leak somewhere leaking fuel vapors to the atmosphere.

I've thought about doing that. In fact, I have already tried to clear the code with my reader, but after a few days, it came right back. The other problem is that this problem occurs sporadically. I cannot seem to predict or replicate the driving condition(s) which causes the car to rumble/lurch/cough. Sometimes it happens when I'm at a traffic light, and sometimes it doesn't. It's quite random, although it does *seem* to occur more often when the car has been running for a while.

So, even if I was able to clear the code long enough for it to stay off while the dealer inspected it, chances are that the car would rumble/lurch/cough right at that time, knowing my luck. :-/

All of that sounds potentially quite expensive to track down and fix. I really don't know if the cost is worth the benefit. The question is whether or not the amount of money that the dealer would offer me (if I got this problem fixed) for the trade-in would be comparable to the worth of the car minus what I'd pay to repair this issue...

A few days is all you need, isnt it!

Just on off-chance, try replacing the gas cap.

Test for that by leaving cap off and see if lite comes on.

The EVAP code is likely unrelated to your problem. The most common cause of a P0440, IMHE, is failure of the purge valve or purge flow sensor. Ford recommends replacing both at the same time and they (used to?) come as a kit of sorts. Sensor, valve and a couple of hoses. Both are located in lines directly below the battery tray. It sounds like the idle may be surging a bit when idling in gear. Try cleaning the IAC valve. Cleaning only works long term about half the time, but it's worth a shot on a car soon to be traded in.

Okay, a bit of a disclaimer: I know NOTHING about car repair. Absolutely nothing. I've never even changed the oil in my car. :( So I really cannot do any of this on my own, and have to rely on my local Pep Boys. In your estimation, how much do you think it would cost (or rather, SHOULD cost), in parts and labor, to diagnose/clean/fix the various valves as you suggested?

Basically, I'm looking to avoid paying the ridiculous $100 "diagnostic fee" that Pep Boys would automatically charge in this case, so I would like to drop off the car and basically tell them to fix X, Y, and Z only. As I mentioned, I know nothing about car repair, so I am going by what you and the other kind folks have suggested in this thread! :) If, in your opinion, you believe the issue is with the IAC valve (and, to me, it certainly sounds correct), then I'll just tell the mechanics to repair just that. Thanks.

Whoa! The car needs to be diagnosed properly, there's no way around it. The things I mentioned are common problems but are not the only problems that can cause your symptoms. If you tell the shop to replace the purge valve and sensor, then clean the IAC it may well solve the problems. If not, you've spent that money needlessly and then you will have to pay for the proper diag and repair on top of it. What is wrong with $100 for diagnosis? That's about 1.5 hours. A proper driveability diag can take anywhere from .5hr to 2 hours or more. Most shops will even roll over a part of that fee into the repair if they do the repair.