Intermittent Check Engine Light

[txtchr]

This is my first post, although I've been reading the forum to try to determine what is going on with my car. Any insight would be appreciated.

I have a 2001 RX300 (2WD), original owner, 53000 miles. I have done all the scheduled maintenance and oil changes every 3000 miles. Only repairs I have done to the vehicle are a new battery in July, 2005 and then ironically a week later the check engine light came on and I had the front 02 sensor replaced. Nothing until July of 2006 when my battery died again. After bringing it into the shop (not Lexus since I'm out of warranty), my mechanic determined that my battery was fine but my alternator needed to be replaced. He replaced it with an AC Delco alternator and fully recharged my battery. Two weeks later while waiting at a traffic light, the car stalled (although everything kept running inside--like the AC and the CD player). The car started up again, but my red battery light came on. I immediately drove back to my mechanic who determined that the alternator was bad and was not charging my battery at all (this caused the computer in the car to shut down, he said). He replaced the alternator and once again recharged my battery.

One day later my check engine light came on (along with the VSC and the Trac OFF light). Back to the mechanic, who kept it there for a day. He returned it saying that it was a "glitch in the computer system" when the car had shut down due to the bad alternator. Drove for one day and the check engine light came back on. Back again to the shop. He said that one of my other 02 sensors may be bad, but that after he cleared the codes he couldn't get the check engine light to come back on. I took the car back home. One day later the light came on again.

This time I had the auto shop teacher at my high school look at it (he's an ASE master mechanic). He ran the codes and told me it was a P1130. He advised me to check the seal on the gas cap, go for a long drive on the freeway (I usually only drive short trips) and see if the light went out in a couple of days. I followed his advice, and sure enough, it did. But then I started having trouble starting my car, with the clock resetting to 1 AM. The shop teacher checked the battery (100% charged) only to find that one of the battery cables had not been connected tightly at all to the battery terminal. No trouble starting it since then.

Now, one week later, down to 1/4 tank of gas and my check engine light goes back on yesterday. I get gas this morning, tighten the cap with more than 3 clicks, drive for 5 miles and park. Get back in the car, start up, and the check engine light is off.

Does anybody have any idea what's going on?

[3sticks]

:)

This is my first post, although I've been reading the forum to try to determine what is going on with my car. Any insight would be appreciated.

I have a 2001 RX300 (2WD), original owner, 53000 miles. I have done all the scheduled maintenance and oil changes every 3000 miles. Only repairs I have done to the vehicle are a new battery in July, 2005 and then ironically a week later the check engine light came on and I had the front 02 sensor replaced. Nothing until July of 2006 when my battery died again. After bringing it into the shop (not Lexus since I'm out of warranty), my mechanic determined that my battery was fine but my alternator needed to be replaced. He replaced it with an AC Delco alternator and fully recharged my battery. Two weeks later while waiting at a traffic light, the car stalled (although everything kept running inside--like the AC and the CD player). The car started up again, but my red battery light came on. I immediately drove back to my mechanic who determined that the alternator was bad and was not charging my battery at all (this caused the computer in the car to shut down, he said). He replaced the alternator and once again recharged my battery.

One day later my check engine light came on (along with the VSC and the Trac OFF light). Back to the mechanic, who kept it there for a day. He returned it saying that it was a "glitch in the computer system" when the car had shut down due to the bad alternator. Drove for one day and the check engine light came back on. Back again to the shop. He said that one of my other 02 sensors may be bad, but that after he cleared the codes he couldn't get the check engine light to come back on. I took the car back home. One day later the light came on again.

This time I had the auto shop teacher at my high school look at it (he's an ASE master mechanic). He ran the codes and told me it was a P1130. He advised me to check the seal on the gas cap, go for a long drive on the freeway (I usually only drive short trips) and see if the light went out in a couple of days. I followed his advice, and sure enough, it did. But then I started having trouble starting my car, with the clock resetting to 1 AM. The shop teacher checked the battery (100% charged) only to find that one of the battery cables had not been connected tightly at all to the battery terminal. No trouble starting it since then.

Now, one week later, down to 1/4 tank of gas and my check engine light goes back on yesterday. I get gas this morning, tighten the cap with more than 3 clicks, drive for 5 miles and park. Get back in the car, start up, and the check engine light is off.

Does anybody have any idea what's going on?

[SKperformance]

Need a new code to see if it is the same problem.

Your biggest problem is a mechanic and not a technician.

[txtchr]

Need a new code to see if it is the same problem.

Your biggest problem is a mechanic and not a technician.

So far the CEL has stayed off. If it goes back on, I'll get the code and post it here. To me it just seems odd that both times I have battery problems (one year apart), within a week the CEL comes on. And, I realize my problem is the mechanic. Isn't that usually everyone's biggest problem if they don't know and trust a reliable, honest mechanic? That's where I'm at now, which is why I came here. Thanks.

[SKperformance]

No problem ,get the code for free from any parts store and it should all make sense.

Or invest in a code reader as it works for any 97 and newer car and some earlier which is an investment in itself . It only costs about 30 on ebay and saves time ,money ,gas and not knowing with out help.

[txtchr]

So far, after one week, no CEL. But, this may end up being a battery issue. Start up this morning was difficult, and the clock reset to 1 AM. When I got to my high school (work), I had the auto tech teacher check the battery. With the engine off, it showed (if I can remember correctly) voltage at 12, then when we turned the engine on, it went up to 13.5. He also connected another gadget to the battery that showed "replace battery" after he had typed in the specs for the battery. His advice: replace the battery and go from there. I went to O'Reilly's (conveniently located across the street from the school) and purchased a top-of-the-line battery for $74 and had the shop teacher install it for me. When I drove home this afternoon, it almost seemed as if the car had more power.

We'll see if the CEL comes on and if this solves the CEL problem. Perhaps this was what was causing my woes in the first place. I'll post back what goes on from here. Electrical issues can be a nightmare, and I almost wonder if when my alternator failed in July that my electrical issues began.