vurjt91

Driving on Interstate highway the other night and set cruise at 75 mph. A few minutes later the cruise kicked off and the CEL, ! Triangle, and VSC light came on. Scan indicates P0171 and P1171. I've only had the car since August and have put close to 5k on it. First time for this issue. I have a great Indy mechanic to go to, just wondering if I can give him some hints. FYI. Ran a can of SeaFoam through it about two fill ups ago. Only use 93 Octane Shell gas. Car is driving fine. Any experience with these two codes?

P0171 states "System Too Lean (Bank 1)
P1171 states "Fuel Performance / Port Injector"

fwhomeboy

Run a tank of non-ethanol

fwhomeboy

Ok, so, did you take any clamps or hoses off to put in the Seafoam? BTW, what made you decide to put in some Seafoam? Was the car running bad?

vurjt91

I just bought the car back in August and thought it couldn’t hurt to give it some Seafoam. No, I have not had any hoses lose.

fwhomeboy

Ok, so, the problem began with the addition of the Seafoam? Is that right?

vurjt91

No, about two or three fill ups after the Seafoam

ArmyofOne

I would say its coincidence.

What's not coincidence is that injectors can fail. More importantly though, there is a TSB out for the high pressure fuel pumps. If your injectors are faulty, they are each set up to throw codes individually. So if your #4 Injector is bad, the code will tell you that (P0174 IIRC), a broad fuel system code would indicate a faulty pump or pressure regulator (or a filter clogged), but the 171 code could indicate a number of issues:

Dirty O2
Faulty O2
Vacuum leak
Dirty MAF
Clogged Cat (generally not the case)

The two codes appearing together, I would start looking at vac hoses and replacing them if they are old/brittle.

vurjt91

My Indy today said that the bank 1 O2 sensor had some oil on it presumably from the HP fuel pump o-ring that was leaking oil pretty bad. Much worse than the one on the passenger side. Passenger side O2 sensor was clean. Both O rings have been replaced with OEM parts.

I got it back but have not driven it long but for now it's running great.

fwhomeboy

OH Good. Let's keep our fingers crossed. Good find.

vurjt91

So the P0171 code was thrown today but no P1171. Live Data from the scan tool at my Indy's shop shows a misfire on cylinders 1, 3. 5, 7 (bank one). He's thinking the that O2 sensor is faulty. It did good for a couple of days after he cleaned the oil off of it but now is failing again. Going to get the O2 sensor replace after Christmas.

fwhomeboy

Good luck. Let's hope no more oil is getting on it again.

Doublegrants18th

Nice! I agree about Shell. Not long after tried Chevron and my car goes bananas. Same 93 octane. No stp octane boost additives or anything. Especially on PWR mode. You know how that goes. Burnout off the line every time 😂😂😂