420A 2gNT Engine dies while driving.

[Aday320]

Okay, I'm new. I looked for about 20 minutes to find a problem like mine. There were some somewhat similar ones, but not quite the same. I drive a manual 99 eclipse 420a non turbo by the way.
So today I was driving from Montana to Washington, and after a couple hundred miles my car died. Everything was normal, I was doing 80 on the freeway and then all the gauges dropped. There were no immediate warnings, the car wasn't surging, nothing. The only warning was the check engine light which had came on about a week ago. While coasting, I tried starting it but it wouldn't start. After coming to the side of the road and stopping, I tried starting it back up. It fired right up and I figured all was well, probably just hiccuped. I got back on the road and as I shifted to second it did it again. So I pulled back over and popped the hood. I checked all my fluids and took off the gas cap to see if I had pressure. Fluids looked fine although I didn't hear it release any pressure when I unscrewed the gas cap (I had nearly a full tank). I got back in and took off very slowly. It seemed to drive just fine for about 10 minutes when it suddenly died again. I pulled over and decided to let it cool off for about 20 minutes. This seemed to work as it waited about 30 minutes after I left to die this time. Throughout the remaining couple hundred miles to my destination it randomly died 6 or 7 more times. I noticed it always died when I hit about 4k rpms before I shifted. So I drove very mellow and kept the rpms between 2 and 3 thousand. This definitely helped although about every half hour it would die again.
On the way I stopped in at an O'Reilley's since they do free diagnostics. The only code it gave me was for a bad O2 sensor. I don't have the code number right now but it was the second sensor which is the one behind the catalytic converter. The lady at O'Reilley's said this is a very likely cause of my car stalling. I'm not sure I believe her 100% though. Tomorrow I plan on getting a new O2 sensor somewhere and hopefully I'll be able to install it soon (I don't have any tools over here though I do have some family who should).
What do you guys all think? Other things I was considering were ECU, Coil, Vehicle Speed Sensor, and Fuel System related parts. Has anyone had issues like these? I'm really hoping to get it fixed on a relatively small budget.

 

[estoyaqui30]

Just to add some info to this subject, I had a similar issue, car would just shut down while driving. It was the CAS failing. It worked until it got hot and them throw a spurious signal to the ECU. I found that until I got the new one from JNZtuning, I would start the engine and give it a moment to stabilize and then unplug the CAS, it would then run fine. I only screwed myself once in the couple of days waiting for the new one. I went to the store and forgot and shut it off I had to get a ride home from a friend and come back later that night after the car was cold.

 

[Aday320]

No offense taken. And although I did guess quite a bit, I would've spent just as much or probably more taking it to another shop and finding out the problem. The shop that was recomended to me because of its knowledge of electrical systems in cars quoted me $150 an hour to diagnose the problem. On the bright side, now I have a couple extra sensors, and an extra coil in my trunk. I also learned that I can get over 35mpg when I'm not racing it everywhere I go.