DID YOU EVER CHECK THE FUEL PRESSURE REGULATOR!!!!!!!!!!!!!!!!
Codes 181 and 189 have NOTHING to do with the TPS sensor, but are adaptive fuel trim limits reports. 181 is result of the 173 code and 189 is the result of the 176 code.
Work only on THE FIRST CODE GIVEN (173) HEGO indicates rich right side.
Only couple of things to look at. Either the sensor is bad, or you are getting too much fuel. Since you swapped the sensors left to right, that pretty much leaves excessive fuel as the problem.

EDIT: These codes really do not make sense at all. How can you get one side excessive rich and one side excessive lean?

Are you absolutely certain you do not have the connectors for the left & right O2 sensors swapped, because the code combination is goofy enough to sure make me wonder.

 

Good point dial.

Let's name some stuff. Original Right O2 is "A" and original O2 is "B".

1st code (173) read Right, "A" is lean - Left "B" is rich.
2nd code (176) read Right, "B" is lean - Left "A" is rich.

I) If the wire connectors stayed on the correct sides, then the different O2's report the same condition and are probably OK.

II) If the connectors swapped sides, then think Right=Left and Left=Right and you will see that now it is really reading Right is lean and Left is rich - just got the wrong codes since the leads were crossed.

Now I'm not suggesting you are a poor or inattentive mechanic. But I have been under my own 93 and I know the O2 leads come off the same wire harness and sit in a bitch of a position to get at -almost impossible to disconnect because you can only get one hand on them at a time. Pending your particular method, it is possible to accidentally swap the wires from side to side. I even thought of connecting the O2 to the harness and twisting up the wires to the left or counter clockwise before installing the sensor into the pipe just so I wouldn't have to struggle getting the connection later - but I went ahead and struggled anyway - for fun I guess.

If you think this could have possibly happened, you can ohm out the connectors from the HEGO side to the PCM. But why do that when I just noticed that Ford used different wire colors. Those guys are so smart! Whether Fed or CA car, right Hego return to PCM is gray/lt blue stripe, left is red/black stripe.

Oh - now that everything is swapped, and you are confident that you know right HEGO is looking at right bank and left at left, read the plugs again. If you still have a set of left black plugs and a set of normal right ones - well then crap I'm right there with Dial on this one.

You mentioned before you thought you might have a coolant leak. I mentioned too before that such a leak would have to be below the valves to only affect one side. That neans head gasket or cracked head - or cracked cyclinder wall into a coolant jacket. If you get coolant into the exhaust the O2 on that side can get contaminated, short term even, to give a false reading and even sense the O2 in the steam going by it. It would say - hey computer I'm starving for fuel here and then your PCM richens that side. Thus, the O2's read correct but for the wrong reason - a mechanical failure that the controls system has no way of diagnosing.

Do a little more checking. I think the 181/189 codes came because of recent batteru disconnect and lack of learning.

Oh man - too much thought for a Friday night. Where's my beer?

 

Hgey too I happend to think of the gas or oil you found at the back of the intake - i think near the vacuum tree. If you have an auto trans, you might have a bad vacuum mudulator on it. When the diaphrams goe away, you suck up tranny fluid. This could be a source of a rich plug reading and it might contaminat the O2 as well - not sure about hydro carbon O2 fouling. But again, if this were happening it doesn't explain your codes since a vacuum port into the intake feeds all cylinders. But if you are down on tranny fluid - this could attribute to some of the surging you may have felt under load. Obvious check here is pull the vac line from the tree or the mudulator itself - that would give a better indication since it is lower than the vac tree.

 

If you stop and think about the codes, the combination makes perfect sense for switched O2 sensors.
One side shows rich, so the computer tries to lean it out, but in fact is leaning the WRONG side, so the the computer again leans it again and again to no avail till the trim tables limit is reached.
Again on the other side, shows a constant lean condition with the same process repeated, but the computer tries to richen the mixture again till the trim table limit is reached. (Note: the O2 sensor codes never gave a code indicating they could not detect switching, so it looks like they are working, but just reporting the results for the wrong bakn of the engine)
Now I do not know if the connectors are positioned such that they are able to be swapped, but since the engine was removed, it is a possibility. If it can be done, Murphy's law says it will be done eventually if not sooner.

And if this is so, the engine will really run like crap.

Dialtone

 

ok i checked the fuel pressure regulator with the vacuum line test you described Jharger and didnt get any fuel coming out so that should be ok. i would hope that i didnt cross the leads on the o2 sensors, man would i feel stupid. i will go and check those hear in a second. it really sounds like that could be the culprit with the plugs like they are. man i hope it is cause the right side one is a major pain to get at. spent 30 minutes last time just trying to get the plug ins back together on that one. will report back later tonight.

 

I feel for you. If they just made the O2 leads 2 inches shorter or 2 inches longer we'd all be in fat city when it comes to changing them.

Dial - I never had a sensor fail with a rich code. Just the one that it was lean - then, the plugs were black so no, it was really rich. Just like foof found on his, mine had an outer body that was coated in black carbon. The sensor broke internally and exhaust was leaking outside.

Now the O2 electro-chemical reaction inside the unit was still working correctly. It was reading a lean condition and reporting it that way. Reason why it thought things were lean is because the outside ambient reference was now exhaust gas, not air. Normally air at 20% O2 is the reference. Now all of a sudden the reference is ~2% O2.

So 20:2 = .45V O2 return. 2:2 = close to 0 volts return - so lean it would be off the charts probably.

I think you might have been inferring that both O2's might be bad - I guess it could happen. Both were just replaced with new but new does not mean good. I don't know the failure mechansim for an O2 failing with a rich read out. Maybe you can shead some light.

And byt the way, both 173 and 176 say O2 not switching in my code descriptions. With the failing lean I described above, there's no way the sensor could ever switch.

Hey foof - what about your trans vac modulator - is this an issue or do yoy have a manual trans?

 

BINGO switched the plug-ins and now runs like a top!!! thanks guys very much. i would have never found that. the surge has gone away too but i do have a automatic transmission. thank you again i can actually accelerate now! yay.

 

Glad we could help. If you did not do it when you swapped the connectors, you should disconnect the battery for a few minutes to clear the computer settings. This will allow it to re-learn the proper engine control parameters versus the garbage it had learned.
Dialtone

 

Wait a minute. This doesn't prove anything. At least not the to degree that I think your motor was off. I can see a doubling bad affect from side to side if you switch the O2 leads.

So one side is a little lean so the PCM richens it up and the other a little rich so the PCM leans it out. Switch the leads and now you get the PCM leaning out a lean side and richening up a rich side. That would be worse.

But then we have the fundamental question again as to why the 2 sides are not matched with A/F ratio.

Remember, we switched the O2's from side to side to see if the rich/lean readings moved with the sensors. If so, that would prove one or 2 bad sensors. It makes no sense at all that we switch the 2 and now it runs OK. That is like trying to match O2 sensors for each bank of an engine until the engine runs OK. It don't work that way.

Something is masked. Foof - run the thing a coule days and then get the codes read again. I still smell a rat in this.

 

i will run it for a few days and then check back in. so far the check engine light hasnt come on once. with the leads crossed it was leanning a lean side and richening a rich side. now that the leads are where they should be it is leaning a rich side and richening a lean side. when i replaced the intake gaskets there was some cracks in them. could this have been part of the problem with the a/f being different on both sides. there where two cracks on one side and one on the other.

 

You replaced the gaskets the then afterwards got the codes read, 173 and 176, right? If you got codes after eveything was all sealed up, then you should be running the same A/F mix on both sides. If you still have an imbalance, there must still be a problem. I understand the double negative effect of swapping the O2 connectors. That's not what confuses me. I'd like to see the new memory code read. But it's definitely good news that you have no CEL now. It would be nice to know what the problem(s) really were and what fixed it. Intake gaskets, MAF, O2's...

By the way, the Y code the the tech used for that first code pull is for a 300 CID in line 6 cyclinder with EFI. The basic fuction of the controls are the same but since that is an in line 6, I would think there are not 2 banks of 2 sensors.

 

OK. I think I figured this out. When you first changed the O2 sensors this is when the wiring leads got swapped from side to side. When you ran the car, a slight lean on one side and rich on the other got compensated the wrong way on both soids which lead to the 173 and 176 codes. When you swapped the O2 sensors from side to side, you kept the wiring leads right where they were, which were the wrong sides, and thus got the same codes again. Basically, nothing changed and this does prove the O2 sensors are good because you got the same response. When you finally went back and put the wiring leads on the correct sides, the PCM was then compensating rich/lean correctly and thus now you have the right A/F mix on both sides, have all your power back and best of all, no CEL or codes.

Dialtone - this makes sense right?

OK, now I can sleep at night.