SO I payed $70 and bought an AC Delco sensor to replace my Bosch front O2 sensor.

At first I thought it worked as when driving around town it didn't surge at all.

But when I get a few blocks from home, the starts surging and when I leave from a stop, sometimes it will nearly kill. But not kill like one would think, it's like the RPMS just dip all the way down to idle and then climb back up from there. Power is still fine, lights don't flicker or anything, it's just the powertrain that loses power.

Also, I've been chewing through about 10 miles to the gallon... HIGHWAY! It's even worse driving around town.

I sealed the headers, put a new O2 sensor in, now what?

I couldn't even get to school today partly because accelerating and cruising were just aweful, it felt so unsafe driving like that. When accelerating, the RPMS would fluctuate maybe 75 rpms in either direction. Now they are fluctuating between 100-200 rpms. You can't imagine how difficult it is to drive like that.

Have you checked for vacuum leaks?

I know you just did a top swap but have you done a compression test?

You might have a bad gasket.

On your top swap did you have the heads rebuilt?

I never had the heads rebuilt.

Never did a compression test.

Checked for vac leaks but never found any.

If I had a bad gasket I'm sure I would have blown it by now, wouldn't you think? My oil and coolant look absolutely perfect so no leaks or anything there.

And I'm running fine at the track so I don't think it's something that would cause a loss of power.

Start by checking the following and I don't care if it's new. I had someone that just replaced wires and one of them was bad from the factory.

Spark Plug Wires
Fuel lines for leaks
IAC Actuator
Vaccuum lines
Scans/Codes
Transmission Fluid Level and Condition

so you didnt get the heads checked or anything before you threw them on there?

No. I wasn't really aware that it might be an issue. That's the kind of thing people leave out in "Top-Swap Guides" and order forms...

I added 3 to my AE tables from 0%-35%. It helped with my part throttle KR a bit, which was nice and also the tranny seems more responsive but it's still surging.

If I had MY laptop charger instead of Ema's I would still be tuning but her charger won't work with mine but both work for her laptop.

My plug wires are stock from when I bought the car. I've never had a misfire ever so I think those are ok.

No leaks in the fuel lines. However, I don't have the normal "elbows" in them, they broke so I have rubber fuel line hose clamped to them. Not the best/safest solution but it works.

I just cleaned my IAC a week or two ago. The idle got a little softer but didn't help the problem any.

I need to find some kind of combustible spray that I can use to check for a vac leak. I don't think the last stuff was flammable.

I was throwing a P1133 code because of the headers and leaks. Pulled it from the PCM and thne it started giving me P0133 and P1134 instead. Well, now I have a brand-new AC Delco front 02 sensor and sealed the headers again. It's still giving me the P0133 code but the P1134 hasn't showed up again. I'd bet if I enable the P1133 again it would throw that code instead.

I've checked the tranny fluid once since the rebuild. It looked fine and smelt fine.

I think I'll pull plugs today and get some better vaccum detector crap.

EDIT: Just used some carb and choke cleaner. No vac leaks anywhere...

Well a good rule of thumb around here is if you pull the plug wires off (which you did for the top swap)chances are you'll need new one. I'd swap those out.

So you didn't have the heads worked over prior to install. Get a compression check. You may have some blow by on a valve.

I checked the plugs. They all look just fine, #1 has a little brown discoloration but WAY less than when I pulled the stock plugs.

I'm going to lay some info down so there isn't any speculation and so it's all laid out for anybody to see.

-Bought the car August of '06
-Started modding in December of '06
-Top-swapped the car, finished on the 14th-15th of July
-Did my first PTuner scan on September 21st
-First MAF tune on September 27th
-Started chugging on the night of September 28th
-Reloaded previous, UNEDITED .bin in hopes that I just had a bad MAF tune. NO CHANGE!
-Was told that the chugging was likely tranny related by board members.
-Tranny rebuilt on October 22nd, included new torque convert.
-STILL DOES THE SAME THING. Albeit, it has been getting worse
-Last week, replaced front 02 sensor, chugging believed to be cause by running too lean. Sealed headers as well. NO EFFECT.
-Today, added 3% to all AE tables between 0% TPS and 35% TPS. Throttle response and part-throttle KR got better. NO CHANGE IN CHUGGING.
-Today, sprayed carb cleaner around engine, NO LEAKS.
-Today, checked plugs for discoloration. No discoloration that would cause this problem.
-Today, used ohmmeter to check plug wires. NO RESISTANCE, wires are good.

I've always been very careful with my plug wires. The car isn't missing, it's an entirely different "chugging" feeling. I can't even explain how it feels.

It's WAY to slow to be caused by an engine revolution or anything connected to it.

The speed of it increases AS ACCELERATION INCREASES! Meaning, if I'm accelerating like a grandma around town, it's very slow but just as forceful. But if I'm accelerating hard, (NOT WOT) it's quick enough that it jars your head in the seat. And yes, it is that forceful. Imagine driving the car but "pulsing" the throttle as you accelerate.

Read all the parameters again with the PT. IAC, MAF, TPS, all the good stuff. Something may show there.

http://www.scandepot.net/viewscan.php?pk=4497

That's my most recent scan and I can't see **** wrong with it either.

Have you tried unplugging the MAF to see if it ran any better?

Here is what I scan: My Scan

Your LTFT are all over the place. What are your STFT?

NO, should I though?

I could go for a quick drive right now... but still, I'm not sure ti will help.

It's to see if you have a bad MAF sensor. If it runs better with it unplugged.

Could a faulty TPS be a culprit?