MR.T

P1457 is not the gas cap code, so you can eliminate that from your "parts to buy list"

In the old cars there used to be a vent built into the gas cap that would vent the gas tank and relieve gas fumes into the open air. Without a vent of some sort the gas tank could collapse due to negative pressures. Think of leaving a plastic gas can out in the sun with the cap on, then putting it in a cooler place.. It'll actually start to cave in.
An evap system is the cleaner way to vent the gas tank, it takes the fumes of gas that have evaporated from your fuel tank, sucks them through a charcoal filled canister, and through a series of solenoids/valves, sends the fumes back into the intake to be burned in the combustion process.
It does this because the fumes that vent directly off of your gas tank are a much worse pollutant than the catalyst managed fumes from the tail pipe.
Do a wiki or YouTube search for a deeper understanding, that's how I learned. You can also look up "black magic" and evap codes should be in there somewhere, haha.



Are you doing your own work? if so, I can walk you through diagnosing the codes. Billman did a write up that I used, but I had to go a step farther.

If you're not doing your own work, be prepared to visit the stealership, or a shop that knows evap diagnostics and has the equipment to diagnose/repair. You may be going back multiple times though. 90% of techs just throw parts at these problems, there is never any true diagnostics involved.

acklavidian

I do the work myself, but I thought I would just buy a new module to replace the assembly. Why do I need to run diagnostics if I can just replace the assembly for $30 or so. I'd rather just replace the assembly than try to repair it. Unless its really easy or something.

MR.T

There are many components in the system. If you start just throwing parts in there you're likely to be 1,000$ in the hole by the time you finish.

MR.T

The p1457 code doesn't pinpoint which solenoid is bad, it just tells you that there's a leak on the "canister to purge" side of your evap system, the other side being the "gas tank to canister" side of the system. That's why you have to go through some steps to diagnose properly.

The only affect evap should have on your car's performance would be in the form of a vac leak, possibly causing a lean condition depending on how bad the leak was. I experienced some performance issues, but I didn't throw any other codes as a result.

acklavidian

Well I didn't have time to work on it this time this weekend so I have done anything to it yet, but this morning my engine light turned off after being on the whole week. This morning it ran great too. However, at lunch it started running really bad. I was almost empty so I put some gas in it. It ran a little better, but only in random intervals. It will run great for a few minutes then it will start misfiring, and die.

MR.T

damn dude. sounds like you have a few things to address.

if you're truly getting a misfire, check these to stickies out.

https://www.s2ki.com/s2000/topic/867...ave-a-misfire/

https://www.s2ki.com/s2000/topic/659930-misfire-thread/

but if you're not getting any specific misfire dtc's that's kind of a hard one, because there are all types of things that could make your car "feel" like it was missing. maybe look into MAP related problems in the under the hood sticky section.

sounds like your evap dtc might be intermittent. being that it went off on it's own let it ride for a bit, but if it comes back you'll need to address the issue.