tried it all

[aguavekid]

i have a problem need advice.my 94 explorer sport has a stumble and slight backfire when i accelerate. i had almost the same problem before and replaced the mass air flow sensor which solved the problem. not this time. i have done a compression check with good solid 138lbs in all 6 cyls. no leak down. replaced spark plug wires, plugs,MAF sensor. the fuel pump and fuel filter i replaced in august of this year.fuel pressure check at the fuel rail is right up to spects.i did a vacumn test to check catalytic converter and it tests as no blockage.gas mileage is still great, and i can get right up to freeway speeds with no problem.then if i put my foot into it it sort of gulps, then you can hear a slight backfire or pop in the exhaust. after a few miles i will get a check eng. light and when i check codes it is code 176 which is "lean condition showing in left bank' i have swapped oxygen sensors from one side to the other and still get same results,so i haven't replaced oxygen sensors as yet. anyone with a suggestion out there??

 

[MazdaGreg]

Well, from what you describe, i'd go two ways on this one. The first one would be that i'd use a Digital Volt Ohm Meter to test the Throttle Position Sensor. I had a Ranger that did something similar every time you touched the throttle, and it could have a dead spot in it. That however, does not explain the lean code. To me, that means that you have a Vaccum leak somewhere. You changed the plugs and wires, and I assume that they are installed correctly, since you have your mileage still. See if you can find some kind of Vaccum leak on that side of the engine. Injector Oring, Intake Manifold. See if you can hear a hissing. Some people use Carb Cleaner to spray around a running engine to see if they can find the vaccum leak.

Good luck