Some codes I'm receiving in 01' 3.0 5spd

[upallnight]

Before pulling the intake manifold, see if you have a vacuum leak. P0174 is a lean condition code which can results in a misfire. A lean condition code is mostly associated with a vacuum leak.

I would look at the plugs that are not foul as that is what a lean condition can do to them.

[DillonInCO]

I've looked for leaks as best as I can without having a smoke machine...DrRick, which machine did you get that was only ~$60? The ones I've seen are more expensive.

As for the plugs, why would it be lean only on those three cylinders, especially since they're in different banks?

[bcredliner]

Driving your X with the symptoms you have shouldn't cause any harm. That said, I would get to a good Indy shop and get the smoke test soon. The smoke test you want to get is a pressurized smoke test that is done when the engine is not running.

As mentioned, vacuum leaks are a common cause of misfires. They are also a common problem as vehicles age.

[bcredliner]

The video shows nails used to make contact to the voltage output. It is not dangerous. Many amp meters have alligator clip connections that would be attached to the nails.

Misfires due to problems like vacuum leaks are often random cylinders.

[smi2710]

so i have replaced my two front o2 sensors and cleaned MAF. I am still getting the P0141 sensor 1 bank 2 error now

all other codes seem to have gone away running too lean , misfires etc... so far so good knock on wood

I guess i should check the disa valve next or move on to rear sensors?

car has 124k on it and plugs were done at 98k and i replaced valve cover gasket at 110k

[bcredliner]

Rear sensors are part of emission system.

Have you eliminated the potential of a vacuum leak?

[DillonInCO]

If it helps, my issue turned out to be that one of the hoses going into the PCV valve had come loose. So check the DISA for sure, but if it looks OK, I would start checking for vacuum leaks under the intake.

[smi2710]

i have glanced over real quick for vaccum leaks i seem to get the code if i park the car for at least 30 minutes then take off again and i usually get it withing 5-10 min

have not checked disa yet

[DillonInCO]

Sorry to bump this thread again, but the SES light is back on. Codes this time:

P0455 - Evaporative Emission Control System Leak Detected Gross Leak
P0135 - O2 Sensor Heater Circuit Malfunction Bank 1 Sensor 1
P0161 - O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 2

So the O2 sensor codes are the same as before. No misfire codes or codes about running lean this time, though. No change in power or gas mileage either (still averaging around 20). I cleared the codes and the O2 sensor codes came back within 50 miles, but not the EEC leak code. The car drives fine and has been without SES for months.

This time around I'm noticing a couple things that are indicative of the DISA valve---whistling noise part throttle, and occasional unexpected acceleration as if a turbo just kicked in---so I plan to go ahead and rebuild it before anything else. Before I spend money on the O2 sensors as well, is there anything else I should check, specific to the heater circuits? Maybe a fuse or relay has gone bad? Or maybe a connector is loose somewhere?

[bcredliner]

O2 sensors may be fine. If there is a problem upstream the O2 codes may be only a symptom of the core problem. I would have a smoke test done to check for vacuum leaks. If not a smoke test I would let the engine idle and spray starting fluid where a vacuum leak could be and see if engine increase rpms indicating a vacuum leak. First place I would check is the plastic air intake tube. If vacuum leak is there you should be able to see it.

I would expect the DISA valve to be rattling if it is bad but assuming it is the DISA valve you should fix it right away as it can cause serious engine damage.