Wife on way home today had restricted preformance pop up. She said she was going up a hill engine light came on and restricted preformance popped up. She said car ran the same never changed at all. After about a mile the restricted preformance message went out.

I broke out my scanner when she got home..ERROR code ..p0171 p1111

I fiqured the code may be the result of a new air filter I replaced last week that was the wrong size ( fram needs to get the right part number for jags)

So I just ordered a new K&N air filter.

My question is does this seem right?
Should I look elsewhere?
Could it be a vac. hose?
I cleaned the MAF last week with MAF cleaner (I am a pro at this thanks to my old Toyota)

 

P0171= Bank 1 running lean:
-Air Leak between MAF Sensor and Cylinder Head
-MAF Sensor
-Fuel System, faulty injector, fuel filter (another easy fix)
-Exhaust Leak before Catalyst

P1111 normal ( nothing to worry about)

I would start at the MAF Sensor, try cleaning it with MAF specific cleaner fast and easy to do. Its located just left of the air box on the intake tube. If your scanner can do real time or freeze frame data, get the number of the MAF sensor itself and we can compare.

 

Yeah I cleaned the MAF last week with MAF cleaner
I also replaced the fuel filter 2 weeks ago and run Lucas fuel injector cleaner every tank or every other tank full.

It may be a exhaust leak but it is quite, I did put a new o2 pre cat sensor in last week. Do you think maybe it's not tight enough?
I used a $250 delphi sensor not a cheapo.

I'll check all vac hoses and see if it triggers again.

 

Some guys use either brake or carb cleaner for checking for vacuum leaks. Brutal suggests water in a spray bottle.


Sometimes just cleaning the MAF is not good enough, but what do I know.

 

Never use brake cleaner to clean out your MAF, use CRC Mass AirFlow Cleaner, its the best.

 

I suggested MAF cleaner and achy stated he cleaned with MAF cleaner.

 

ohhh my bad Rick! I guess I missed that, then if thats the case just get a whole new MaF sensor, simple

 

MAF Sensor at Auto Zone $65.00, checking for vacuum
leaks $0


There can be several reasons why the vehicle is popping the 0171 code.

 

This might help http://www.gusglikas.com/images/Auto...otos/P0171.pdf

 

Is it definitely a correct, compatible, O2 sensor? There are multiple kinds and it matters.
Any chance the connections are wrong?

Consider watching the waveforms of all 4 sensors. If the other plans don't work out.

 

Thanks guys I am going to check for vac leaks, I would think that is prob. it..

The o2 sensor I use I have checked compat several times it says it's the right one.
http://www.amazon.com/Delphi-ES10939...2005&carId=010

I got to thinking I had this happen once, the o ring around the MAF was cracked and would throw codes.. I am gonna check that!!!
It is possible the MAF could have went bad after cleaning I have heard of it happening.

I am also why I am at it going to clean the throttle body really good..

 

Hey Achsklic, I just tried that link for the O2 and it said IT DOES NOT FIT! Please double check for the 4.2 Paul

 

Really everytime I check it says it fits a 2005 jaguar s type 4.2 front.

Where did you check it at?

I checked it again, with one on ebay and it says the same thing that it fits a 2005 jaguar s type 4.2 front.
http://cgi.ebay.com/ebaymotors/Delph...Q5fAccessories

 

On the amazon link you posted? checked another link and it said it was ok?

 

Yeah I triple checked on the amazon link as well as the ebay link and both confirmed it was the correct one.

Wonder why it said when you checked it was incorrect?

You got me paranoid...lol
I just checked another site it says it's correct as well
http://www.autopartswarehouse.com/de...ELES10939.html

 

This post sure caught my eye.

I have the same issue with RP, when going uphill. After a few tanks of fuel, I can now replicate the RP Message at will.

It only occurs when traveling uphill (>= 5% grade), at speeds greater than 40 mph, with a full tank of fuel.

After 20-30 miles off of a full tank, the uphill climb will no longer throw the RP.

I can't pull codes on the go unfortunately, as my laptop died and got replaced by an ipad.

I am suspecting a bad fuel cap seal first as I don't have any vacuum release when I release the fuel cap.

Hopefully this helps.

 

Just a quick update from this morning...

After 5 months of check engine (threw codes for cat, throttle body,maf), my CEL is clear & no resticted performance.

The answer... New gas cap

I had known this in years past and just let this slide because I didn't think cat & O2 sensor codes would be related to a gas cap.

So to the OP, this is definately one of the cheapest places to start.

Hope this helps.

chris

 

Kudos to you! I never gave the gas cap a thought.

 

Update mine started throwing the code about every 3 -4 miles. I would clear it then down the road it would pop up again. Yesterday evening my K&N air filter arrived I took the junk new fram filter out, sparyed throttle body cleaner in the throttle body and wiped it clean, installed new air filter...

So far I drove quite abit last night and today and not one cel has popped up..WOOHOO hope it's fixed....Also I like the beefier sound it has now with the K&N filter!

 

Had been getting restricted performance/CEL (DTC P0171) for about a week. Restricted peformance only lasts a couple of miles, then goes out. Used a chemical smoke stick to look for vacuum leaks, and found none. MAFS looked clean, problem kept surfacing. Cleaned the throttle body while the induction duct was off and took another look at the MAFS. There are ports on either side of the, I guess it's a pitot, and one side has what looks like some sensors in it. Used a brigt light and noticed a small, maybe 1/4X1/8" piece of grass up in there. Got it out and have driven ~100 miles with no further CEL. The moral of the story is, when you change air filter, wipe out or vacuum the filter housing box.