02 Ford Escort *** Too Lean

[cresiefu]

HELP PLEASE!!!!!!!!! My 2002 Ford Escort ZX2 49,858 miles - Diagnostic Reads" Too Lean ". Anybody have any suggestion?

O2 sensor or possibly Filter problem. Someone I know suggested " Spark

Plugs" but I am thinking Spark plugs are totally unrelated. This is causing
my Service Engine Soon light to come on.

Thanks for your help!

[mightymoose_22]

Too lean means that you have too much air and not enough fuel. The situation can be from a number of things, including a vacuum leak allowing too much air into the system or blocked up fuel injectors not providing enough fuel. It could also be something like a bad O2 sensor providing bad data and making the computer think the conditions in the fuel/air mix are different than they really are.
It can be a difficult problem to diagnose as there are a number of possibilities. I'd suggest first inspecting for a possible vacuum leak. If that doesn't turn anything up then maybe just do some preventative maintenance if it is due... change fuel and air filters, maybe the O2 since it is 5 years old, run an injector cleaner through the gas tank... andything else you can think of that might effect the fuel/air mix.
You will need some special diagnostic equipment to do the tests necessary to pinpoint your problem and know what exactly is wrong... so just take a stab at whatever makes sense.

[Davescort97]

As mightymoose 22 says it could be a vacuum leak. If it is you will hear a whistling sound coming from the engine. Could be a defective hose or the hose has come off of the intake manifold. I need more information. Does the light come on all the time or does it just come on and off as you drive it? Are you getting PO 174 or PO 175 diagnostic code? The MAF (Mass air flow) sensor just before the filter on the intake ducting measures the amount of air going into your engine. If it is bad it might make the mixture too lean. When it is disconnected it makes the engine run richer by default. Can you unplug this sensor to see if your light goes out?

[cresiefu]

Originally Posted by mightymoose_22

Too lean means that you have too much air and not enough fuel. The situation can be from a number of things, including a vacuum leak allowing too much air into the system or blocked up fuel injectors not providing enough fuel. It could also be something like a bad O2 sensor providing bad data and making the computer think the conditions in the fuel/air mix are different than they really are.
It can be a difficult problem to diagnose as there are a number of possibilities. I'd suggest first inspecting for a possible vacuum leak. If that doesn't turn anything up then maybe just do some preventative maintenance if it is due... change fuel and air filters, maybe the O2 since it is 5 years old, run an injector cleaner through the gas tank... andything else you can think of that might effect the fuel/air mix.
You will need some special diagnostic equipment to do the tests necessary to pinpoint your problem and know what exactly is wrong... so just take a stab at whatever makes sense.

Thank you so much for the input..i am going to have this looked at by a mechanic that basically said the same thing you did. However, I am a female and don't have any knowledge PERIOD and I don't want to get dupped, like I already have when buying this car. I will keep in mind all the points you have made. Thanks

[cresiefu]

Originally Posted by Davescort97

As mightymoose 22 says it could be a vacuum leak. If it is you will hear a whistling sound coming from the engine. Could be a defective hose or the hose has come off of the intake manifold. I need more information. Does the light come on all the time or does it just come on and off as you drive it? Are you getting PO 174 or PO 175 diagnostic code? The MAF (Mass air flow) sensor just before the filter on the intake ducting measures the amount of air going into your engine. If it is bad it might make the mixture too lean. When it is disconnected it makes the engine run richer by default. Can you unplug this sensor to see if your light goes out?

Thank you also for you input. Last week I was driving and my car sounded like the wheel or something was getting caught up in my wheel. I looked under the car and there were two wires just dangling there, but NO Service Engine Soon light. Well, a couple of days later it popped on and I noticed it felt like it was pulling or like misfiring when I go 40mph or higher. The Service Engine soon light has been on and stays on. I started searching for these Forums because it just Shut OFF one day while I was at a stop light. It started back up and hasn't shut off since, the next day I went to the AutoZone and they tested it and told me it was TOO LEAN and I believe the Diagnostic Code was PO 174. Do the codes help narrow down what parts may need to be replaced. Thanks again for all your feedback, this is great.

[cresiefu]

Just to add, I now don't see the loose wires that were hanging and could never determine where they orginated from...

[mightymoose_22]

A lot of times the code can tell you exactly what is wrong, but the code you are getting is only informing you of a condition. As said, there are several possibilities that will take further investigation to narrow down.

[Davescort97]

PO174 is "Mixture too lean". Loose wires wouldn't reattach themselves. lol.
Could have been some wires in the road you picked up. Don't know. A too lean mixture could be caused by faulty Mass Air Flow (MAF) sensor. It could be caused by a faulty Air Intake Temperature (IAT) sensor. The fuel filter couild be clogged. The fuel injectors could be restricted. You could put a bottle of fuel injector cleaner in your gas although I don't think this would help. You could have a vacuum leak. Since you don't know about cars I will explain. When the pistons go down to pull the mixture into the cylinder it produces negative air pressure in the intake. It sucks. lol. There are many systems that rely on vacuum (negative air pressure) to work. If somewhere in the vacuum system there is a leak, the engine sucks too much air which makes the fuel mixture too lean. Also, a vacuum line off of an emissions device may make that device cause the engine to run too lean. Something as simple as a clogged fuel filter could cause a lean conditon. Run a bottle of fuel injector cleaner in your tank. May not help but it can't hurt. Bottom line is there is not enough fuel or too much air entering the combustion chamber. As you can see there are many and varied things that could cause this.

[Rickottman]

Could be a fuel filter but my 97 escort ran lean at 175000 and that fixed it but it shoulldent at 50000