P 1128, 1130, 1115 1119 Help!

[diff operator]

Ok,
As in the title I have a 2000 Boxster 2.7 and I'm getting the following codes:
P 1128, 1130, 1115 1119
The car seems to idle a little low. somewhere about 650-700 maybe, the car has a light vibration at idle, nothing major. When I drive the car is a little rough right on throttle tip in but the car revs fine and drives nicely.
I've searched and seen a variety of causes and solutions proposed.
I tried disconnecting the MAF and drove to see if I noticed a difference, witch I did not. however, I didn't clear the codes first so I'm not sure if I should have or not.
The car had previously sat for a while before I got it, is it possible there is a fuel pressure issue?
By the way, I tried removing the oil cap, there was a slight vacuum, but it was easy to remove, the idle did increase when I removed it.'
Any help would be appreciated

[JFP in PA]

P1115 and 1119 indicate a problem with the heaters on the O2 sensors ahead of the main cat on both banks. P1128 and 1130 indicate both banks are over rich. Most likely issue is a wiring problem that has taken out the heaters on the O2 sensors, so I would start there first.

[diff operator]

Interesting, I thought I had just read that it indicated that they were lean?

[JFP in PA]

Originally Posted by diff operator

Interesting, I thought I had just read that it indicated that they were lean?

This is a common problem with internet discussions of P1128 and 1130. On the early cars (up to 1999) which had the 5.2.2 DME, P1128 and 1130 were the codes for an overly lean condition. However, on the 2000-2001 cars with the 7.2 DME as well as the later 7.8 DME, the same two codes (P1128 and 1130) were for an over rich condition; exactly the opposite condition.

Again, this one of many examples of why I tell people that use out of date or incomplete bootlegged service manuals to always double check their information; unless you have the complete OBD II diagnostics manual for the 986 series, including the more than 100 supplements covering issues like the above, you could easily end up chasing your tail..............

[diff operator]

Would it make sense that both O2 sensors ahead of the cats went bad at the same time? The exhaust certainly doesn't look or smell rich. Would that cause the slightly low idle?
Does anyone have input on the MAF reset / testing the MAF?
Could it be an issue with the fuel pressure regulator?

[JFP in PA]

Originally Posted by diff operator

Would it make sense that both O2 sensors ahead of the cats went bad at the same time? The exhaust certainly doesn't look or smell rich. Would that cause the slightly low idle?
Does anyone have input on the MAF reset / testing the MAF?
Could it be an issue with the fuel pressure regulator?

Multiple O2 sensors very rarely fail at the same time, usually that is a wiring issue.