Ok fellas, don't beat me up too bad, i have'nt had any luck with my problem on the other boards so i'm gonna ask here. This is my post from the other board.


"Haveing a problem with the engine wanting to "cut out" from time to time. It mainly does it at crusing speed, 50-60mph. The check engine light comes on, it seems like regular intrivals, with the engine miss following. Sometimes a bad miss, sometimes hardly noticable. Checked the code and its showing o2 sensor lean, and thier was one for the injectors. I've replaced the o2 sensor, fuel filter,and had some used injectors i put in it. Is thier something i'm missing? I'm not getting any codes on anything else. Thought maybe a leaky inj. showing that the engine is running rich and in turn the ecm leans it down too much. But with diffrent injectors, not sure thats the problem."

Ok, like i said its a Mercury Tracer, 93 model with 28000 miles. I'm showing code 41 in memory, i've checked vacume lines today and the only thing i see is my PVC has restricted flow thru it both ways. Don't know if that has anything to do with it. Any ideas?

 

Do you also get a 41 from the KOER test? What engine is in that tracer? Any breaks in the wires between the sensor and the PCM? What is the fuel pressure? Is this engine MAF or speed density? So many questions.

 

KOER shows no codes, i have no idea if the wire is broken anywhere, it all looks to be in good order. It has 1.9 liter engine, and i'm not sure about your last question. It has a mass air sensor on the breather tube.

 

So it's mass air. I really am not at all familiar with that engine, so just trying to get a feel for basics.

If you're getting pass 11 from the KOER test, that suggests that your fault is intermittent. If you clear CM and test drive it, does the CM 41 come back immediately? Can you get a feel for what conditions trigger the CM 41?

Check fuel pressure. Where the fault appears to be intermittent, this may mean rigging it up so you can monitor fuel pressure while driving to see if it is falling off at some point.

Looks can sometimes be deceiving when it comes to wiring. We need to be reasonably sure that all of the connections between the O2 sensor and the PCM are good, and that there are no bare spots or other wiring problems.

Is the O2 sensor a three wire or four wire sensor? If a 3 wire sensor, make sure the engine ground strap (or wherever the exhaust system would be grounded) is good.

 

I can clear the codes and drive it and it does come back code 41. I will explain a little better when it does it. I can get in it while the engine is hot or cold, i can travel about 1/4 mile the cel will come on for about mile or two. Then the cel light sometimes stays on and some times goes out, then a few seconds later i can tell that i'm looseing power and if i continue with the accelerator at the same position, it will gradually get worse untill its missing so bad the it starts "bucking". At that point i let off the gas and let it slow down to about 35-40 mph, ease on the gas and it will run good for about another mile or two. Also when it just starts missing i can push push the accelerator quickly to the floor and let up and it will imediatly run fine for a mile or two. All the while the cel will come on for a few miles and then go off for a few miles. Like i said i'm not sure of the fuel pressure, i'll have to get something riged up this weekend to check that. Also go thru the wireing and make sure thats all ok.
Would this thing possibly have two o2 sensors? When i bought the one they did'nt ask which one i needed so i would assume not, but i'll check that too.

Thanks Shorty for your help,

 

> i can push push the accelerator quickly to the floor and let up and it
> will imediatly run fine for a mile or two.

If a car does this, I would start looking at a clogged EGR system, would remove it and clean everything out. I don't know if Seafoam would help.

 

ok, its fixed. it took a toothpick and 5 minutes. there was a microscopic piece of lint covering the little wire electrode in side the mass air flow sensor, scraped it off and it runs great now.


thanks again for your help!