my 97 4.0 Mazda B4000 has been running rough lately and was getting worse and finally these codes show up-0133 and 0171. On initial inspection I did not find any leaks, cleaned MAF and throttle body and went ahead and Replaced the bank 1, o2 sensor(was only $30), but did not help.
After further inspection I think my upper intake gaskets are bad. I confirmed that with a test i read about by blocking the air intake at the MAF(disconnected) and seeing if the car stayed on. It did and I heard a sucking sound from the upper air intake area.
From reading several past threads about this it seems like it most likely the upper air intake gasket but also could be the fuel rail to lower intake gasket as well? Does my diagnoses seem correct? And since I am in there should I go ahead and replace the valve cover gasket (it is leaking) as well as the the lower intake gasket?
It seems at Advance auto the fuel rail gasket only comes with the valve cover gasket kit, So I would have the vavle cover anyway.

How much should I expect from an indy to complete the work? dont know if I want to do it myself.

any info would be great.

thanks,

mark

 

If you haven't already torn into it, maybe try confirming your leak test by rigging a cat converter & sensor safe propane sniffer, using an unlit propane torch, with a length of tubing attached & a sports needle on the free end as a probe. Pass it along the suspect area & listen for a change in idle speed or quality as the engine gets a whiff.

If you come to confirm a leak, maybe try re-torqueing the fastenrs to spec, in the specified sequence & see if you get positive results.
If no joy, check here for Advance Auto discount codes http://www.retailmenot.com/view/advanceautoparts.com & here a link from our "Tech Info" thread https://www.ford-trucks.com/forums/2...ke-gasket.html for a tutorial by member Rockledge, who has done this & let us know how it goes.

 

Paw, Paw, thanks for the quick reply. I will look into the cat and sensor safe propane.

I did try to re torque the easily accessible bolts around the torx bolts. they seemed tight. Did not attempt the torx ones.

Yes, have read all the rockledge tutorials and will use a guide if I decide to do it myself.

I did talk with a mechanic and he said he needs to look at it but replacing all gaskets, including valve cover, lower intake etc would be around $700(he said he did the same on a recent 94). He said the upper intake is only a few hours labor but did not give me a price on that. He said he needs to inspect it. But to me while torn down and after 140,000 miles may as well do it all? Seeing as I definitely need the valve cover replaced as well.

Yes, never buy parts at Advance auto without coupons, rarely shop anywhere else.

thanks,

Mark

 

OK, now back to the two trouble codes you posted, the P0171, system too lean cyl bank-1 & the P0133, slow O2 sensor response on cyl bank 1, suggests that the bank-1 O2 sensor might be old & slow, sorta like me & in need of replacement & if both upstream sensors have 75-100K miles on them, could be the root cause of your trouble code & driveability woes. Change Both up stream O2 sensors at the same time with OEM, or like designed, so the computer can keep fuel trim for both cyl banks in balance.
Unhook the battery B- cable when replacing them, to wipe the corrupt fuel trim tables stored in KAM. Doing so, also wipes the cold & warm idle strategy stored there. After the engine has completely cooled down, perform this relearn procedure Ford Truck Enthusiasts Forums - View Single Post - high idle problem to maybe prevent driveabiity problems & to help the computer begin to rebuild new fuel trim tables with input from the new O2 sensors.

 

ok, well, I did replace the one in Bank 1 two days ago and did the Bank 2 about a year ago. (reading now I should have replaced both at the same time). i(or the mechanic) have replaced the sensors several times(2,3,4 times) since i bought it in 2000. I have had many issues with the truck over the years but really in the last 5 years it has finally settled down.

anyway, when I did replace the Bank 1 sensor(Bosch) the other day I just cleared the codes from my code reader. That is not good enough? I will disconnect the negative terminal from the battery and see if that changes things.

thanks

 

OK, if the bank-2 sensor is only 2 years old, its likely ok.
Why in the world have you had to replace the O2 sensors so many times, the answer to this might be a clue to the root cause of your problems.????
That's not normal, unless you had coolant leaks that got to the O2 sensors, or they got a whiff of silicone spray, ect.
Anyway, let it cool completely, disconnect the battery B- cable for a few minutes, or open a door, turn on the light switch, ect, to discharge/wipe KAM. Turn the electrical loads off, reconnect the battery B- cable, then perform the cold & warm idle relearn, drive it some & scan for codes again & let us know how it goes.

 

did the disconnect, did the idle relearn and it is still bad. can barely make it up the hill. just drove a mile or so.
I drove it a few days when it was not too bad it could basically run once it got going and warm. but after 3 days or so, i could barely make it home it was getting so bad. That last day is when it threw the codes.

 

OK, good feedback on the KAM wipe, idle relearn & test drive.
After thinking about this some more & re-reading your posts, gotta ask, has it been sipping coolant over time???? If so, that could explain why so many O2 sensors have been going bad. Ever notice a chocolate milkshake look deposit on the engine oil dipstick????

 

yeah, early on i had some serious issues. Each year lots of money to clear codes and sure enough another code would show up and I would drive with it till the next emission inspection a year later and then spend more money.

One year I went through it with a different mechanic and after $1,200 bucks things were fixed-that may have been 8,9, 10 years ago- can't remember. In the end that mechanic said one cylinder had less pressure than the rest. Don't remember the details. Really didn't know what it meant at the time.

The last significant issue was about five years ago when I had a similar issue but not as bad. One mechanic could not fix it-just tried coil, wire and all plugs except one-don't know why. a different mechanic at that same time then replaced the coil and one really bad looking spark plug-it was jacked.

but really had run fine since and not may problems in the last 8,9,10 years or so.

spark plugs have been replaced at least 3 times, if not more.

spent a lot of money in a 15 month period 10 years ago on my truck and car and that is why work on them now.

 

no, never had any coolant issues. did a drain and fill myself about two years ago. never, ever overheated.

 

Honing in on the lean/O2 sensor codes, how much will it cost to do the job without replacing the lower intake manifold gasket? If it's significantly less, then I would just replace the upper intake and fuel manifold (a/k/a fuel rail) gaskets.

Because you mentioned a valve cover gasket leak, then of course you will want to replace those gaskets while you have the top of the motor apart. I recommend using Loctite on the valve cover gasket bolts.

One way to further confirm whether the lower intake gasket is shot is to have a UOA done.

 

yeah, that was what I was thinking. If it is just those top gaskets I may do it myself.

Tha fuel rail gasket for a 97 at Advance auto comes in the same kit(vs50368) as the valve cover gasket. I just got the upper intake ones yesterday-only $5.99. The dealer would be around $125 for all those. All felpro would be around $25.

there is some confusion. Reading the last post on rockledge's tutorial(post from 2014), someone says the gaskets changed by ford and were made thicker and the felpro ones are iffy. And also some years have a paper gasket both on bottom and top of the fuel rail. His was a 98 though.

 

just an update for future reference..... Removed the upper manifold and found the most rear fuel rail stud-hex bolt-was loose (I only re torqued the manifold bolts-not the hex ones as suggested by Paw Paw above).
Even though I had the upper manifold gaskets on hand I went ahead and put everything back together after re torquing the one bolt, thinking that was the issue and it would be no big deal to go back in if needed.
Sure enough there was no improvement but apparently in the process of removing the manifold (struggling with the egr tube) I broke off the egr vaccum tube nipple on the side of the manifold. I still test drove it because the vacuum is so great it held the tube on pretty well. I appeared, I needed to go back in a do the upper plenum gaskets; but now I also needed a new upper manifold as well with the broken nipple(could not find the nipple)

Thinking I would get a used one, I called a Ford Ranger junkyard here in Atlanta and the owner informed me that it is not worth getting a used one because they have found used ones only work 1/3 of the time. I got a brand new one (with gaskets) delivered in two days (Amazon Prime is awesome) for $120.

Replaced the old manifold with the new one and things seemed to go pretty well (it runs 90% better) but I do still have a slight hesitation, shudder at low rpms and start ups, from a stop. Still trying to track that issue. Maybe need to go back in and do the fuel rail gasket?

Also: In looking at my receipts of work done in the past (and there was a lot), I did apparently have all gaskets replaced only 20,000 miles ago- or at least they charged me for the whole kit that included the lower intake gaskets and valve cover gaskets along with the upper and fuel rail gaskets. So who knows what was done and what I was charged for exactly. That was in 2008 and I dont go to that mechanic anymore. From that point though the car has run well for the most part except for one issue a few years back.