Tzakeran

Ok, slide along a patch of ice and smacked my front end into the rear driver tire of a honda CRV. Now I've got some rough idling, which was happening before the collision, also have a starter that doesn't start half the time. I notice in the city the engine idles rough, and has power. When I go back up to the mountain towns at 9,400 ft above seal level, I obviously lose power. The idling doesn't get worse at altitude, but it does 'hunt' while under power very often. I've not replace my 02 sensor since I moved up 4 months ago. The car had been in FL for it's life, so it's used to sea level 02 I suppose. I went to AutoZone and they gave me a single code P1131. Says possible causes could be: Misfire on Bank 1, Vaccum leak affecting bank 1 only, Fuel injector problem bank 1, or Engine mechanical condition. The code also states it 'detected bank 1 02 at its lean limit' I assume bank 1 plug 2? I can do basic maintenance and fluid changes, but this is beyond me. Any feedback is much appreciated. Thank you in advance!

Bert

The O2 sensors aren't made for certain altitudes. I'd see about the code. When have the plugs and fuel filter been changed? How many miles are on it? What year and engine? Try running it with the MAF unplugged and post the results.

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Bert

R.S.LOGAN

^ x2. If it's running lean at sea level it must be miles out at altitude .As suggested , check all vac hoses / pipes .Dependant on what's fitted , also check pcv / hose / engine breather .

FordMan59

I had codes PO171 and PO1131 on my '02 Escort last year, replacing the upstream 02 sensor cleared both codes.

Bert

O2 sensors will cause codes but usually not missing at high altitude.

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Bert

FordMan59

I don't know whether the DOHC ZX-2 engine has any rubber elbows in the pcv line or not, but the standard Escort's SOHC engines do and it's common for them to split or crack creating a huge vacuum leak and poor performance. That would be one of the first places I'd look for a possible vacuum leak.