94 Explorer w/ ecc codes 176 AND 177. Advise??

Nathan, what were you thinking when you wrote: : My 94 Explorer w/117,000 miles has been running very poorly lately. : The symptoms only occur after driving on the highway for a while : (about 50 to 100 miles). It loses power and runs really rough like : its misfireing and blows carbon out the exaust. I checked the stored : codes and got a 176 (HEGO Sensor indicates system lean [RH]) and a 177 : (HEGO Sensor indicates system rich [LH]).

Nathan:

Start here

for more help in diagnosing your problem. Note that my engine stored a different code for the HEGO rich condition. My Explorer was also a '92 so maybe the codes changed by '94. I can't remember when they changed the engine computer software but I was thinking it wasn't until '95.

Good luck,

jeff

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I'd be interested in what you find out. Mine does the same thing.

When I take a cross country trip, several hundred miles out it starts sputtering for a few minutes and then recovers. One one trip from Raleigh NC to Chicago, it did this the whole way. The codes are the same as what you reported. I replaced the O2 and MAF sensors, but a year later on another trip, the same thing happened. Mechanics cant find any problems.

The car runs fine during normal daily driving to/from work/errands.

I basically dont go on any long trips with it anymore.

Sorry I cant help, but you're not the only one with the problem if thats any consolation. My theory runs something toward fuel injectors icing up or otherwise not injecting but I 'm just showing my ignorance here. The problem goes away when the car sits for awhile, then reoccurs after a few hundred miles.

dickm

That sound like exactly the same problem. Me and my wife decided it is just a home body truck cause it doesn't like long trips. I too had the mass airflow sensor replaced a couple years back and it did not help. The problem seems to be getting worse. In fact, I drove it during thanksgiving break for 450 miles each way and it did it the entire way at 13 mpg. I don't think its an injector issue because it is blowing carbon out the exaust which tells me its is trying to burn too much fuel. (ie not a clogged injector). I ordered a fuel pressure regulator. I will post to this thread if this does or does not solve the problem.

Thanks for the link. It will be helpful when I replace my FPR. As far as the codes go, there are two O2 sensors with different codes for each one. The RH for lean and rich are 172 and 173 respectively. The codes changed in '95 when ford started using the ECC-V computer.

Oh, I forgot that the fuel milage dropped down to around 13, just like yours.

I didnt think it was the fuel pressure because my codes were from the same side, RH I think... i'd read the codes after a long trip and all I'd see RH lean, RH rich, RH lean, RH rich, RH lean... well, you get the idea.

I never noticed any carbon/exhaust smoke out the back of mine. Of course, I never really looked. I was too worried about getting home.

Dick

Well, I replaced the fuel pressure regulator and no change. Guess I'll keep digging around.