2000 SEL with 171 but no 174?

Got a check engine light on our 2000 SEL and took it to Advanced Autoparts for a reading... the guys says it's showing 171. He said it wasn't showing anything else. Assuming he didn't miss additional codes, is this likely the same problem everyone else has had and documented here? or does the absense of the 174 code imply it's something else? any ideas?

I'd hate to devote $100 bucks and an afternoon to fixing the wrong problem... :-)

Much appreciated.

Seems a little odd in that the six cylinders effectively "share" the metered air volume. That of course leaves fuel, but the three injectors in bank one (171) would then have to all be "under metering" fuel while bank two (174) were correct. Anyway, you might try a different reading by a different store/person. My older obdII scanner requires you to "scroll" to see additional codes. Perhaps he/she "missed" that ?

You could also be in the early stages of the issue.
The reading is from a separate oxygen sensor in each exhaust manifold line, and it is possible that 1 sensor is catching the issue before the other....they should be reading about the same value.....but it is unlikely that they are both exactly the same......but I'll bet they are close.

It is also very possible that the vaccum leak caused by the weaking isolators is not causing the same exact leakage on both sides.....and so it could show up more on one side than the other....resulting in 1 sensor reading a more lean condition than the other.

It the isolator bolt replacement has not been done...that would be a good place to start.

very much appreciate the quick replies, busboy and wiswind. Maybe I'll take it for another reading to see if the 174 really is there and the guy just missed it, but I guess I'll start looking for a weekend (probably after it warms up a bit!) to do the isolator bolt fix...

it never ceases to amaze me how much solid advice good folks like you provide on these boards!

very much appreciate the quick replies, busboy and wiswind. Maybe I'll take it for another reading to see if the 174 really is there and the guy just missed it, but I guess I'll start looking for a weekend (probably after it warms up a bit!) to do the isolator bolt fix...

it never ceases to amaze me how much solid advice good folks like you provide on these boards!
The First code I got was a 171 and nothing else. Reset and went to Auto zone again after about 400 miles of driving until the light came back on and got 171-174. Now have my own code scan tool.I did do the TSB on mine and everthings fine now.. I did pull a code at work off a guys Ford Expedition and only got 171 so you could just check all vacuum lines. One of his vaccum lines was bad.

thanks for the reply, garync1... I'll check the lines first, since I can do that easily in the garage in 15 degree weather. :-)

Forgive the ignorance - but would that imply just a visual check of all the lines that get disconnected when you are in the process of replacing the isolator bolts, or are their more that I should check? are their any tips / tricks to checking the lines (like coating them with soapy water or something)?? one last question - is bank 1 on the right or left when I'm looking at the engine? (I'll focus there first, I guess, since I'm getting the 171 and not the 174)

thanks for the reply, garync1... I'll check the lines first, since I can do that easily in the garage in 15 degree weather. :-)

Forgive the ignorance - but would that imply just a visual check of all the lines that get disconnected when you are in the process of replacing the isolator bolts, or are their more that I should check? are their any tips / tricks to checking the lines (like coating them with soapy water or something)?? one last question - is bank 1 on the right or left when I'm looking at the engine? (I'll focus there first, I guess, since I'm getting the 171 and not the 174)
Yea really thats about the only thing you can do the back ones are hard to get too. First feel around for loose lines. Make sure there snug. You can spray soap water out of a spray bottle and see whats around. But if the isolator bolts have never been done they may end up being your problem in the end. Its really not that hard too do. Others on here have found good deals on the parts. How many miles do you have on your 2000 mine is a 2001 and it did not light up until 74,000 if i recall...

we've got 73,000 miles on our 2000... so I'm due to fix this issue! I'll check the lines now, and if I can't find anything, I'll do the isolator bolts when it warms up a bit and I can work outside without issue.

we've got 73,000 miles on our 2000... so I'm due to fix this issue! I'll check the lines now, and if I can't find anything, I'll do the isolator bolts when it warms up a bit and I can work outside without issue.
HMMMMMMMMM..70,000 seems to be a trend..

Yeah, it's due to be done.

My 2000 LX 3.8 never did throw the infamous 171/174 - but I was getting consistent pinging unless I added premium gas or octane booster. I did some research and decided the isolator bolts were the root cause. After doing the isolator bolt fix, it ran great.

One warning: The DPFE tends to fail at about the same time the isolator bolts need replacement (it's a reasonably priced item and an easy DIY job). It's not related to the isolator bolt fix, but I haven't been the only one who has done the isolator bolts - and then needed a DPFE a month later.

You might try to see if they can read your long term and short term fuel trims with their obd-ii device to see if the other bank is running lean also.

They should be able to read those in real time. These are generic OBD parameters and should be able to be read by most readers.