P0171 Error

[tsgrpr97]

Dealership = $$$$$

I had motorvac done last year on wifes car $165. A lot of independants charge a flat fee for the service.

Edit. Sorry it was $200.


But this isn't going to remedy any lean codes

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[shadow460]

IMO, the motorvac service is a $70 solution to a $5 problem. If it's done right, then yes it'll clean more gunk out, but it's a heck of a lot cheaper to use a $5 bottle of fuel system cleaner every few months.
I've used Berryman's and Gumout. I don't think there's one brand that's better than the other, but Berryman's is $3 or so at Wal*Mart, whereas you can sometimes get Gumout as a freebie depending on what specials Autozone is running. My Dad and my father in law have both recommended Berryman's to me.
Wow, motorvacs are running $200 now? Pick a fuel system cleaner and save $195.

As for the DTCs, I would check all the vacuum lines. My '98 F-150 had an elbow rot away and some vacuum lines rubbed up against a wiring harness until they wore through. I'd replace those personally and then read the codes again. If you can afford a basic code reader, get one and get a Haynes book so at least you can research your problem a bit and know if the mechanic is trying to rip you off. Case in point for me was when I took my truck in for a $40 repair and they told me I'd need $525 worth of work. I performed the exact same test found in the Haynes book, proving them wrong. Their shop turned as quiet as a church mouse.

Best of luck. I hope you nail the problem.

 

[toms89]

One cylinder bank running lean can be caused by vacuum leak as mentioned but less likely only because it will typically cause both banks to run lean. But it may just be a matter of time before the other bank also reads lean if vacuum leak. Bad O2 can cause perceived lean bank. Generally when the O2's go bad they do read lean. The front O2s are used for tuning so only need to check those. The rears only check for cats function. A intake manifold leak near the head can obviously cause one bank to run lean. A few other possibities not mentioned are exhaust leak before the 02 sensor (exhaust manifold) or a missing cylinder. Surprisingly missing cylinder can cause a lean reading due to the passing of air through the cylinder along with unburned fuel. But 02 reads 02 content with relationship to the outside air not fuel so..!! These items would be bank specific along with a bad O2 sensor.

 

[mikeexpedition]

So far 200 miles with CEL reset after new fuel filter and running some sea foam and no more light. Knowing my luck it's not the end of it but for now it seems good. Thanks for all the responses.