i am now 100% positive that my problem is and has been my battery. The guy at my local G.M. dealer graciously let borrow a battery for a week. it has been 2 days and no light just went to autozone and no codes are pending so I think I found my problem. i have to get the battery back by Friday so I'll be getting a new one then. I apreciate the help from everyone! The time and dedication from everyone whom helped me I am in debt to you. i hope some time down the road i can help you as much as you guys helped me, THANK YOU.

SJC...

I look at this thread and the one I started to see a commonality that will help others in the future with this code and our hard learning experiences.

P0171 as Foghorn experienced was a bad connection from his negative battery cable to the engine block.

P0171 as Billboost37 experienced was a bad battery cable with a little corrorsion inside.

P0171 as San Juan Cruiser experienced as a bad battery terminal.

In each case the code and light while intermittent and frequent was caused by a fluctutation in electrical voltage. This change in voltage, no matter how minor was clearly wreakiing havoc and causing us the P0171 code that the manual says "Good luck on this one" for a diagnostic procedure.

We have a common cause/solution. YIPPPEEEEEEEEE!!!!! Another cleared up mystery to add to the BC knowledgebase.

One thing I'd like to add here is my voltage before was running any where from 14.3v to 14.9v with a good battery the average readings are up to 1volt lower. Also the positve lead going to the fuse panel from the batt (one under back seat)was pretty hot(never noticed before because I let the car cool real well before working on it) now it wasn't even hot right after driving the car.

I got a check engine light today.

Figured for sure it was a Lean Bank.. it wasn't

Week and a half.. all clear on the 1997 after replacing a negative battery cable.

(Now off to figure out my P0336)

I had 10 days of bliss w/o any SES lights and 11 days of bliss before P0701 came back into my life.

Talking with Pat (1993 SLE) and his father (aka Mechanic) check grounds, check grounds is what I hear. I think back to SJC and his POSITIVE terminal causing his issue. Silly me..never checked under the positive cable boots for corrosion. Went and did it right away.. it'* bad (Pat got a picture of it). I've already placed a call to have the cables ordered to a local dealership at my mechanic buddys price (he used to work there).

New positive cables will be going on asap. This issue is going into my rearview one way or another. And it'* worthwhile saying..it didn't exist before I changed my battery for NO REASON AT ALL!!!!!! (Truck needed one..so I tossed the car batt to the truck and put a new Optima in the car)

ok here are the pics of the corrosion that was on the positive battery cables

New cables were ordered and may possibly be in today. Would be on the car tomorrow evening.

Wow, those are pretty nasty looking! I assume you'll let us know the results once the new cables are installed?

I would guess so, he'* been whining about it long enough...lol. :P


On topic: It would be informative if this really solves his problem too. That would make at least 2 of 2 that were solved with this fix and would give us another likely place to look for future instances.

I'll definately keep everyone posted.

As a side note, when I got dropped off at home yesterday (I commute) I found my maxifuse cover off and the battery cable connection to the relay center exposed. Had a bit of corrosion as well.

This lends more merit to the advice we give to clean all connections at all ends. At the very least this would be a future problem for me, however we have see problems arise from less corrosion.