I have a 2002 Grand Caravan that's running a little rough and has the P0171 code. I've read a ton all over the Internet on what to look for, but I'm wondering if anyone can narrow it down.

When I get in the vehicle after it's been off awhile, there's a gasoline smell (gas, not exhaust.) It's somewhat hard to start, and will run rough for 1-2 minutes, then it clears up and is fine even on the highway.

The gas smell seems to indicate a fuel leak maybe? Could this help narrow down what to check? What would be the most productive place to check first? I've heard everything from fuel filter, fuel pump, to hoses with fuel, hoses for the air, and the sensor itself.

Full symptoms:

- Engine light
- P0171
- Starts rough
- Runs rough for 1-2 min, then fine
- Gas smell in passenger compartment after sitting off for awhile (overnight)
- 144k miles, no major repairs (so far)

 

here's my thought

bad injector(s) allowing fuel to flow into cylinders on shutdown(gas smell)
hard starting open/bad injector(s) affecting fuel psi on start up

 

P0171 is bank 1 lean meaning that basically the engine is running lean.

I agree with the leaking fuel injector, the only way to find out is to remove the fuel rail, or at least raise it up high enough to see the tips of the injectors. Turn the key to the run position, do not start, and see if there is fuel dripping from one of the injectors, if there is, you need to replace that injector or injectors that are leaking.

Replacing the faulty injectors may clear up the lean code. Not reset it, repair the problem. The code may be the result of the bad injector(s).

 

Ok, I took it into Cueter Dodge in Ypsilanti. They said the fuel pump relgulator was bad, and it was putting out 150psi when it should be doing 90 or 70 or something. So they replaced it and the fuel filter, requires tank removal. $820 later, ouch, they said I needed new plugs, too (which was true). For $192 I told them I'd do it myself, so I did. The DTC P0171 is gone, but the engine still runs a little rough at startup (though a little better thanks to the plugs) missing some cylinders, but eventually all kick in (I think.)

And the gas milage is still terrible, something like 15-16 mpg when doing 70 on a flat stretch of highway, when I should be getting about 25. How rough would the engine be with only 5 cylinders? It seems pretty smooth. And if it's not the fuel pump or filter or injectors (I think they cleaned them) then what?

 

It was 90PSI it was putting out, and was supposed to be 50, I just talked to the repair guy at the dealership. Evidently they did not inspect the fuel injectors. If it cost $820 to do that thing, how much will they charge for replacing or cleaning fuel injectors? Oh my god.

 

You can't really inspect the fuel injectors, you have to remove the fuel rail to even get them out. Even so you can't tell if they are bad by looking at them. If it was running with that much fuel, it may take a little while to clear out. Also it could have damaged the catalytic converter depending on how long you were driving it like that. You could have a faulty injector, but at about $80 bucks a pop I would want to know for sure if there is a bad one.

 

Well looking at the bill, they claim they cleaned the injectors, the carb, etc. Given they didn't solve the problem, I took it back today. We'll see what they want to charge this time. Presumably they tested the injectors if they cleaned them, but I don't know.

But they charge $90/hour, it says right on the bill. I bought the exact same Champion spark plugs they use in the car, and wanted to replace, for $35. Special super-ooper-dooper platinum top end plugs, don't even have to gap test them. So if they wanted to charge $192, what's the other $157 paying for? Almost two hours of labor? I did it myself in 1 and I don't have many tools much less years of experience doing it every day. And I know they're not paying $35 themselves for those same spark plugs.

 

$35 a plug! Must be they have a huge markup, my liston the plugs is $8.10 ea. Time to find a better dealer.

 

Hehe, no, the $35 comes from the auto supply store, about $5 per plug x 6 + tax.

But I know the dealer is not paying more for them than the auto parts store is (and probably less), and that's wholesale, not my retail + tax price. So even assuming they paid retail for it, there's still a $157 charge for putting in six spark plugs on top of that.

Well it's noon of the next day and they haven't called me back yet, so here goes nothing.

 

Well, an update. They decided it was the upstream oxygen sensor,$308 including tax. If it were the downstream one, I'd have done it myself.

The thing works well now, thank god. $1100+ for all their fumbling around, and that includes me replacing the spark plugs myself instead of paying them $200.

Oh, I forgot to mention, after the second takeback (the O2 sensor was on the third) they "adjusted the parameters of the computer because it was thinking the system was trying to burn E85 ethanol). The car was noisy. A few days later, I looked under the hood and saw the air filter was not attached and that there was a pressure sensor plugged in and hanging there. I took it back and then they told me it was the O2 sensor.

Needless to say, they did not leave me with a feeling that I had gotten a good deal. But you'd think the upside of a dealership would be quality service, if expensive.