O2 sensor or MAP sensor?

Since getting my HPT software Ive been doing nothing but trying to fix some problems and cannot figure out where to go next. Im getting low O2 readings and fluctuating MAF readings. Ive cleaned the heck out of the MAF, but not sure if its still bad or not as nothing really changed. My car is running extremely lean and my timing is way early. Ive had kr (my 3.6 is back on not the 3.4) up into the 10s. It aslo is running hot (over 200 yesterday and its usually dead on 180) I did have to replace a vacume hose that was leaky, may still have a vacume leak but wont know till tomorrow. My a/f ratio is obviously way out on the lean side.

Short of changing out my MAF (last resort) I think I will start with replacing my o2 sensors. My car has 126k on it and Im sure they havent been changed.
Is there one I should replace before the other that controls A/f ? Any ideas before I start buying new parts?

This may be important...code p1107 popped up...map sensor low input fault.

Have you made any changes to the PCM with the HPT?

none. Ive only scanned

Not that this will solve your problem, but you should be running cooler plugs like AL104s. I'd change them out. Maybe the old plugs can tell a story if it's a major problem.

Change the O2 sensor. It's due time for this anyway, so might as well. Buy an AC, not Bosche.

What are your LTFT values mostly, at idle and cruise? What are your O2 sensor readings at WOT? Are you locking LTFT at zero during WOT?

Check the wiring to the MAF sensor for a short or break.

thanks Aaron. Ive already bought the 104s and plan to do that this weekend. I checked one of the plugs and it had some tan soot on it but still looked ok.

My LTFT values at cruise and idle are not bad (up to 5) but I havent done much WOT with the Kr I was getting. They did lock at 0 last time I did a WOT run.
At WOT my 02 read 911, but its all over the place...as low as 80 in some places.

The MAF wiring looks fine and I cleaned the MAF pretty well but noticed a little discoloration on one of the little sensors that would not come off no matter how much cleaner I sprayed on.

All I can find right now is a Bosche o2 sensor. What is the reason I should avoid this Brand?

too many people I respect had advised against it. I don't know why, but I didn't take any chances. If you can wait a few days, GMpartsdirect.com has OEM sensors for $48.

BTW besides the p1107 code I pulled, Im also getting a p0107 code.
I found this thread:
http://www.regalgs.org/forum/viewtopic.php?t=50729&highlight=sensor

which makes me suspect the Manifold Air Pressure Sensor Connector

can someone please tell me which one is the MAP connector?

This could be my problem.
I bought the Bosche 'cause I cant wait and have to use the car this weekend.
I only bought the one for before the cat.

Update:
replaced front o2 sensor...no change.
I'm suspecting the maf sensor

try this first measure the voltage on the map sensor......the 1107 code is a map sensor circuit low voltage. with that said based off of what my mitchell disk said. you hav 2 different choices: you can replace the map sensor (which is the most logic) or you can replace the pcm( if you have to replace the pcm then you have a lot of problems)

map sensor is located on top right side of engine.........let me know how it goes

Thanks Reese. I replaced the MAP sensor but the connectors snap lock is broken, it may have been a bad connection causing the DTCs. O2 readings are not as low but still not what I would expect. I still need to replace the rear O2 sensor. I replaced the front but installed a Bosch (I may need to replace this with an ACDelco as the Bosch looked physically different then the stock sensor. There were more threads on the Bosch and Im not sure how this is affecting its functionality). Ive ordered a new MAP connector from Intense. So far no more codes...I sure hope it's not my PCM.

Don't worry too much about the rear O2. As far as I know, it's only there to detect emissions from a bad cat converter. If you're not seeing emissions codes, I wouldn't assume it's bad.

If the Bosch you purchased was designed to replace a factory Riviera sensor, it should work fine. My concern was long-term reliability. I'd leave it in since you already bought it. I really doubt the Bosch is causing your problem, unless you got the wrong sensor.

Bob... not real familiar with the codes w/o names and the pc is running a macro at the moment.

One of the things you can do to see if you have an issue with the maf is unplug it. If the car starts running better than you know it was the maf.

Thanks for all the help on this. I did unplug the MAF yesterday and there was no change.
The car seems to be running better now, I did replace the plugs and wires which may have helped the rough idle. Im not getting a code so far so that may well have been the MAP sensor.
My timing is way early, possibly due to the lean condition Ive been running. If no more codes pop up I think I can start tuning. LTFT and STFT are all over the place.
What should I expect my lowest O2 reading to be? Theyve improved now but some are still as low as 115.

What do you mean by "way early" timing, and when are you logging this (cruise, WOT, idle)?

O2 is normally fluctuating below WOT. It may be anywhere between 115 and 900, constantly changing, like a heart scan. At WOT, ideal O2 value should be 930-960. 800s are low (lean). 1000s are high (rich).

LTFT is all over the place meaning from what to what? How high, how low?

My timing at idle is -26 and never gets above negative numbers at WOT.
LTFT are anywhere from 2 to 8.. not horribly out but not smooth by any means.
8 at idle.

After a good hour of driving I'm getting no codes. Looks like it was the MAP sensor. The connector isn't in great shape but I don't think it was an issue in this case.

excuse me for being a little noobish at this but,
Something is wrong.....20.60 psi boost???? with a 3.6?
I just finally converted my chart display to psi and see a spike of 20.6 coming from the new MAP sensor. 2 deg of Kr at the same time.

My exhaust cant be restricting and I only have a gutted air box. How can this be possible?
IAT was 46 but still...

20.60 inches mercury = 10.09 psi

Verify your boost units are inHg. Looks about right to me.

well at least i helped you out with the check engine light, but at as far as boost goes........i have no idea, unfortuantely i have a n/a motor:(

AA wrote:

20.60 inches mercury = 10.09 psi

Verify your boost units are inHg. Looks about right to me.

('')
doh! you're right. thank you

O2's will fluctuate.

I've noticed 50-80's and then up into the 800-900 range. Very normal.

BTW negative timing is the way 97 displays it. Not sure if 96 is the same, but 97 shows negative. Multiply your timing by -1 to get the true number.

BillBoost37 wrote:

BTW negative timing is the way 97 displays it. Not sure if 96 is the same, but 97 shows negative. Multiply your timing by -1 to get the true number.

I did not know that. Thank you, now these numbers are starting to make more sense ('')

I call 97 the backwards year. Threw me for a loop as well when I started tuning my car and saw negative numbers.

Then I got sad when I realized there wasn't something wrong and a ton of power wasn't laying there waiting to be used.

BillBoost37 wrote:

I call 97 the backwards year. Threw me for a loop as well when I started tuning my car and saw negative numbers.

Then I got sad when I realized there wasn't something wrong and a ton of power wasn't laying there waiting to be used.

lol yea, I was hoping to gain a little more.
But I just found out my real problem (although the MAP sensor was bad too).
My fuel pump is putting out about 40lbs of pressure and from what my mechanic buddy told me it should be putting out 45-48.
I think Im on my way to the dealer for a new one.