check engine light, p0171 and p1130

[vdop]

Alright well, my check engine light is coming and going with a p0171 code and p1130. Before the light comes on my afr is 11.xx and even dips into "rich". It occurs on the highway. However at idle and city driving, afr is normally around 14.xx. Car is a n/a 2000 5sfe. I have replaced the front air/fuel sensor with a dealer one and the after-cat sensor with a denso, problem persists. Car has SRI/rippmod headers/catback/unorth pulley.

I had the car checked for exhaust leaks.
Replaced pcv valve.
Cleaned IAC by spraying in TB
Checked hoses for leaks.
Have tried fuel additive cleaners including seafoam.

Fuel Filter has not been replaced as far as I know, bought the car with 40k, now has 100k miles. Not sure if this could be the cause since it is fine other than highway driving.

any ideas?

[vdop]

could using bosch wires and plugs cause anything like this?

[unbalancedwood]

bosch plugs (perhaps wires) are not recommended in the solaras at all.

NGK or Denso.

[vdop]

true, do you think it could cause the engine to run lean?

Either way, ngk wire set is already in the mail, and going back to ngk plugs.

[Midias]

What does that mean?

Basically this means that an oxygen sensor in bank 1 detected a lean condition (too much oxygen in the exhaust). On V6/V8/V10 engines, Bank 1 is the side of the engine that has cylinder #1.

Note: This DTC is very similar to P0174, and in fact your vehicle may show both codes at the same time.
Symptoms

You will more than likely not notice any drivability problems, although there may be symptoms such as a lack of power, detonation (spark knock), and/or a hesitation/surge on acceleration.
Causes

A code P0171 may mean that one or more of the following has happened:

* The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters (K&N, etc.) can cause the MAF to become dirty if the filter is over-oiled
* There could be a vacuum leak downstream of the MAF sensor.

Possible Solutions

Possible solutions include:

* In the vast majority of cases, simply cleaning the MAF sensor does the trick. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
* Inspect all vacuum and PCV hoses, replace if necessary
* Check for a dirty fuel filter and proper fuel pressure