Code P0401

Ken, thanks so much for the reply. I had that thought in my mind given the mileage. A shop was supposed to do the test but didn’t. I’m wondering given no loss of power and no odd smell of sulfur, if it could be a clogged EGR tube and/or the vacuum lines to the recently replaced DPFE. Can the tube really be cleaned well or are you better off replacing? I have the new vacuum lines but haven’t installed them. One mechanic wrote that he always replaces those lines on Fords when he replaces the DPFE. The EGR image below doesn’t seem to be for my car, the DOHC 3.0L, 98 Taurus. Perhaps it’s a diagram of the 12 valve Vulcan 3.0L? On my car, the DPFE is on the right side behind and underneath the intake manifold, when standing in front of the car, looking at the engine, and the solenoid is to the left of the engine, a good distance apart... Almost 2 feet.

Also, about 18 months ago, I had a downstream O2 sensor fail. I replaced it with a Bosch... All that was available on a Saturday. I recently replaced both as they should be done in pairs with Densos, which I believe are better, and OEM. But, again, the shop was to test the catalytic converters, and didn’t. Maybe they didn’t think it was necessary. It wasn’t a quality place with knowledgeable ppl, they are having a hard time getting employees.

Curious about your thoughts given the additional information? A Walker exhaust section with the three cats is $425.00 and they won’t ship to NY, and the car is 24 years old, so I am hoping it’s something less expensive, as if do catalytic converters probably makes sense to do entire exhaust as if parts of catalytic converters broken, pieces could be in mufflers, so I now understand.

Much thanks!
Dennis

Oh, the one system I can’t get to run when checking diagnostics is the catalyst systems. Do you know the real drive pattern for my car? All I get are many contradictory instructions online. Thanks again!

Freeze Frame Data.

Ken, many thanks for the reply! This is driving me nuts.

Without a lift, working on the exhaust/cats isn’t an option for me. Though most all EGR components were replaced, including the DPFE, as everyone says that’s usually the cause, it wasn’t melted or anything, indicating a cat issue. I don’t even think the DPFE was bad. So, the clogged manifold channel and ports behind the throttle body and EGR valve were cleaned, as it was very obviously necessary. There was a good deal of gunk in there. Only one guy recommended it. We also cleaned the throttle body itself and I’ve used a few tanks of gas with fuel system cleaner. I ran the drive patterns as recommended but can’t get the catalyst monitor to cycle.

My thought on the one trouble code re: EGR flow restriction, is that the EGR tube is likely clogged and given that attention is a more logical next step, along with replacing the two high temp silicone rubber tubes from said metal EGR tube to the DPFE. That’s $85 vs. $500-$1,500 for new cats and exhaust. The car has plenty of power and there is no odd sulfur smell, though the mileage is near where one would need cats, it’s not a common problem on the Taurus DOHC motor, probably because there are three and (mostly) dual stainless-steel exhaust, not true dual pipes, though.

I would think doing a simple temperature test before and after each car would tell you if bad?

I can’t determine what is causing P1300 - Boost Calibration Fault, or P1100 - MAF intermittent fault or something to that effect. Had both downstream O2 sensors replaced, given the mileage and they stripped one when removing... And had to add a metal ring of some type to rethread? Not sure the effect. Have live data and other reports, will attach. Both sensors getting voltage.

Have some finicky gas caps, keep changing to get rid of an EVAP code (large leak). Having a very hard time getting the catalyst I/M Monitor to cycle, this is the main issue along with EGR flow error code. The serpentine belt needs to be tightened a wee bit but has proper voltage and a fairly new heavy duty (police battery) and a relatively new alternator were installed. I’m thinking if tighten belt, maybe catalyst I/M will cycle?

If you know the exact drive pattern for my specific vehicle, that would be a big help. Can cruise control be used during drive cycle? I have read contradictory statements on that, when driving to check diagnostics and for smog test?

Much thanks!

Ken, thanks for the reply.

Forgetting about the EGR flow issue, can you instead help with these two questions, please:

Can you use cruise control during the drive pattern?

What can be done to get the catalyst I/M to cycle during drive pattern?

Much thanks!
Dennis