It is a 3.1L. For the past year the CEL was on and they couldn't determine anything. They thought that it was just stuck as happens with most older cars. The only code that came through was when the car first died on me and then they referenced the EGR valve. This time nothing appeared. They drove her on several different occassions without any success and they allowed her to sit idle for several hours hoping to pull something, to no avail. A few sensors were checked but I can't be specific. They have no response for the hesitation between 40 - 50 mph either. I was basically told to run it till whatever it is, breaks completely. Each time she dies on me, I have been able to restart her without a problem.
The first time was different, however. We had her die at a red light. Attempts to crank her failed and we had to get her pushed until the tow truck came. The tow driver suggested trying to crank her which she did. He took 2 hours in arriving so she was pretty cold by then. We had him follow us and, sure enough, she died again about 10 mins later stopped at another light. No problems found by the mechanic except the EGR valve. She ran fine for the next couple of months and then did it again. This time they replaced the EGR valve. Ran fine for several months and then died yet again. Still no codes.
We replaced the battery Memorial day weekend (what a bear) but the mechanic ruled out needing a reset (or relearn) since they can't duplicate the problem. So far all they've gotten in codes is the last time we towed her and she showed the EGR got stuck and one other problem (can't remember what it was exactly but it was related to it). They drove her with the computer hooked up and manually operated the EGR valve and found no problems. Their speculation was that some crud had gotten stuck but dislodged since. Per their recommendation we ran some Seafoam addative through. Since that time she can be restarted without problem after dying. It's the increased frequency that has me concerned. On the upside they've charged us no diagnostic fees and are just as frustrated but the downside is no diagnosis
Getting to the point we're looking at a new(er) car