code after fueling up

[occamaroz]

After I got gas the car started to run like ass and stinky. I checked for codes with my predator and p0171 came up with long trims on bank 1 lean, +23 part throttle. I checked the fuel cap and tighted it.

[blue02Z]

pressure check your cap

[FORD RECOVERY EXPERT]

... also could be bad gas.

[occamaroz]

What a nightmare. I changed the fuel filter and all was good for a while but now the car is throwing 02 sensor codes and running lean on the otherside. I have a vacuum gauge inside the car and it's reading fine.

[SSTODD]

The maf can cause lean codes, aftermarket ones more so. maybe clean your stock one with maf cleaner or swap your aftermarket out if you have one.

[Firebirdjones]

Could just be coincidence,,,but the chances of getting a bad batch of gas is ever so increasing. I find the quality not as good as even just a year ago.

But it sounds like it may be time for a pair of 02 sensors,,,,any new codes popping up????

[occamaroz]

The front 02 are only 2 months old and there the factory AC delco so I know there a good. I have been fighting a closed loop idle problem for over a yr now. Once in closed loop and I come to a stop the car will start to idle rough and the idle will be down slighty then afte a few secs it revs back up to a normal idle. I have changed the fron 02's, coolant temp sensor and tps. I couple months ago I swapped the front 02's to the rears and the rears to the front. Problem solved, so I ordered new front 02's and the problem came right back. I have cleaned the plugs twice with electrical contact cleaner and q-tips. Last week I washed the car and the idle problem went away for about 20 mins driving.

[occamaroz]

I did have two new codes both 02 related.

[0rion]

any mods on the car? How's it do in open loop? Notice anything out of the ordinary with the temp gauge on the car? What were your new codes?

[Firebirdjones]

Well unfortunately new 02's aren't always that great it seems.

I just installed a new pair in mine about 3-4,000 miles ago and wouldn't you know it,,,,I get a code for a slow switching 02 sensor right bank. Mine were also brand new delco pieces.

I just installed another new set this past weekend and reset the codes, after about 150 miles of driving so far so good.

It could still be a bad 02 even if they are fairly new. You know what they say about all this electronic crap,,,you just never know.

Do you happen to have headers on the car????

Sometimes you get issues with 02 sensors being so far downstream.

[occamaroz]

Update. I bench tested the 02's and they tested fine. The passenger side one's were carboned up which I burned that off. I swapped front and rear 02's and nothing changed. The lower of the two long trims is reading fine at idle with throttle up goes all the way to + 25 while the upper long trim read negative. I pulled some spark plugs and there all lean. I tried another maf and nothing helped. I tested fuel pressure it's at 58psi. I'm gonna get a can of seafoam and dump that in the gas tank.

[occamaroz]

After a bottle of seafoam and some long highway driving the long trims are getting better on lower one. There now reading close to the same as the other long trim and won't go higher than +1.56. I still have the crazy closed loop idle issue. When I come to a stop the car will idle a littler low and rough for a few secs then the motor will rev back up to a normal idle and stay there until the next time I stop. I am thinking of getting a fuel injector cleaning kit like the one's I've seen online for under $80.