FocusCanada Forums

2000 2.0L SPI Wagon.

So, I got a CEL on Thursday. I've been battling a 0304 for a while, but it's been too damn cold and I've not had the time till now to do any checking.

Symptoms are low idle, sometimes stalling on a stop. That's it, nothing else that I can tell.

So, yesterday I connected the OBDII, and pulled the codes 0304, and now 0171.

0171 is:
P0171 - System too Lean (Bank 1) The Adaptive Fuel Strategy continuously monitors fuel delivery hardware. The test fails when the adaptive fuel tables reach a rich calibrated limit. For lean and rich DTCs:
Fuel system
Excessive fuel pressure.
Leaking/contaminated fuel injectors.
Leaking fuel pressure regulator.
Low fuel pressure or running out of fuel.
Vapor recovery system.
Induction system:
Air leaks after the MAF.
Vacuum Leaks.
PCV system.
Improperly seated engine oil dipstick.
EGR system:
Leaking gasket.
Stuck EGR valve.
Leaking diaphragm or EVR.
Base Engine:
Oil overfill.
Cam timing.
Cylinder compression.
Exhaust leaks before or near the HO2Ss.
A SHRTFT-1,2 PID value between -25% to +35% and a LONGFT-1,2 PID value between -35% to +35% is acceptable. Reading beyond these values indicate a failure.

0304 is Mis-fire on Cylinder 4.

So, I need to know the best way to check out what is wrong here.
Should I possibly run some fuel system cleaner through it, thinking maybe it's a fouled injector on #4...

Or something else? I have no real clue as to what to check first on this. Give me an old Ford Sierra (Merkur) any day, and I can figure stuff out and fix it. These newer vehicles are just too much for me...until I LEARN about them...lol

I pulled all the plugs and checked them for gap etc. All were clean and set correctly. I also took a quick look at the wiring to the injectors, coilpack, and anything else I could see, and all seems well, no corrosion or broken wires that I could see.

I'm pretty handy with the tools, and not bothered by the work...I just need to know how best to proceed.

Thanks for any and all input.

Scorp.

check out the area where the #4 plug wire goes into the head, there might be oil and crap in the 'well', if it has been awhille since maintenance.... do a big old tune-up. plugs & wires, fuel filter. the fuel filter can be restricting fuel flow, for the lean
situation. and the misfire is usually ignition related. (plugs are easier to change than injectors ;) good luck!

0171 I just had.....My mechanic changed my O2 sensor and it fixed it.....as for the other one, I have no idea

Thanks guys. I've already checked the plugs, and leads were new 6 months ago (same with plugs). They are good, right colour, right gap etc. I did think about the fuel filter, I've had the car for 14 months, and not done it yet. I'll change it out, along with air filter as well. I'll also chuck in some injector cleaner (any recommendations of which one?) to flush the system. Should I do that before or after the filter change BTW?

Hmmm, O2 sensor....if that's what fixed yours, then it's worth remembering...any idea what they cost?

Any other input appreciated.

S.

I think that the total was like $135.....

O2 sensor, coil is also another likely suspect (that was our misfire culprit on our SPI last fall).

Hell, if not for the mess of fuel I'd just pull the injectors and inspect them... if they're anything near "bad", just replace them as needed. I'd do all 4 at once as well. Saves you the grief down the road.

Also, I see someone else recommending a fuel filter. Do it! Damn cheap and well worth changing every 20K or so.