Codes...

From the Ford PC/ED:

P0135, 0141, 0155, 0161 - HO2S Sensor Circuit Malfunction (HO2S-11) During testing the HO2S Heaters are checked for opens/shorts and excessive current draw. The test fails when current draw exceeds a calibrated limit and/or an open or short is detected. Short to VPWR in harness or HO2S.

Possible Causes: Water in harness connector. Open VPWR circuit. Open GND circuit. Low battery voltage. Corrosion or poor mating terminals and wiring Damaged HO2S heater. Damaged PCM.

Testing Aides: Wiring. Damaged HO2S heater. Damaged PCM.

A bad O2 sensor could cause the effects you mention. An itermittent problem might even allow your gas mileage to remain decent. Since you are getting both banks (I assume they happen close to each other) this sounds like something systemic, like a bad ground or low battery. Something that might affect both of the sensors equally.

The battery voltage is usually low... i figured it was the alternator. Alternator was replaced a little less than a year ago though. Is there a way to check O2 sensors?

-Mike

Sure, a couple of ways. The simplest is to get an OBDII data logger (like AutoTap) and log the Os sensor output voltage. You can also bench test by removing the sensor and testing it's output voltage while heating it with a torch. Do a Google search and you'll come up with several sites with instructions and comments.

I don't have a data logger... only a code reader. I'll Google for some ways though. Thx.

-Mike

I cleaned off the battery terminals & terminal connectors.. then re-connected them (a bit of battery acid was there).. no more low voltage.

-Mike

Well.. the whole "hestitating" and "stumbling" at low RPM problem poked its ugly head back up. So I got back to the basics.. car requires air, fuel, and spark to work properly. So since I changed all ignition wires & plugs a few months ago... I didn't think it was spark. And since air is easier to look at than fuel... I checked air components first. I pulled off the air filter (aftermarket cool air kit)... air filter is *FILTHY*. I mean *BAD*. I cleaned it about 3 months ago... didn't think it'd get that bad THAT quickly. Needless to say, it's getting cleaned. It's so filthy though.. that it makes me think the IAT and/or MAF sensors are dirty too.. so I'm going to very carefully clean them. After I took off the air filter & put the intake back together... I drove the car around the block (maybe a bad idea, but I wanted to know)... and it ran nearly perfectly. It felt like a 10hp gain even. So I'm going to finish cleaning air filter & clean both of those sensors & then see how she runs. I'll keep ya updated. I still haven't checked O2 sensors.

-Mike

wrote in news:gLwSc.5538$ snipped-for-privacy@newssvr23.news.prodigy.com:

If they ain't broke, don't fix 'em.

Joe Calypso Green '93 5.0 LX AOD hatch with a few goodies Black '03 Dakota 5.9 R/T CC

Heheh.. no codes yet! No MIL either.

-Mike

Well, that's cool :). Gotta love the basics ;).

Yeah. It's down to almost 0 stumble/hestitation.. I'm gonna reset the comp in a few mins.

-Mike