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Weirdness in bogging, shifting.

FriboRage

FriboRage

New member
I can't even think of what this could be. 04 comp g, plog and dp, intake..lately it's been having this issue when I want to go from coasting to light throttle, or light throttle to slightly more, it bogs down and refuses to shift, I have to get pretty far into the throttle to get it to downshift.

It's not like it's revving up but not catching, for example at times I'll be coasting down a road and reaching the bottom of a shallow incline so I will give very light throttle to maintain speed. You know the little kick of power you feel going from full coast to light throttle, almost like a downshift but not as much and only a small rpm change... That doesnt happen.

In fact when I give it the gas, most of the time the rpms rise slightly then drop back down with very little increase of power. Then I give it more and the same thing I have to get pretty far into the throttle to get a downshift or any real response. Before, I could just tap the gas and feel the car wake up from coasting.

Once the car bogged down when I tried to accelerate so that my head went forward a little... And this morning I went slow through a short construction zone and at the end I put a little gas on to get up to speed from like 15 mph trying to get to the speed limit of 35 and the car bogged down so bad when I touched the gas I thought it was gunna stall.

Heavy throttle it acts normal, good power and good boost, normal driving shifts are excellent.

Just cleaned tb and maf, did seafoam, changed plugs, did the downpipe, tranny fluid and filter, this was happening before I did all that, though.
 


Sounds like maybe the torque convertor clutch may be sticking. Check to see if there are any codes. Also, when's the last time fluid and filter were changed in the trans?
 


No SES light I assume. I looked through a bunch of TSB's. I found on stating you could have a faulty MAF...not faulty enough to set a light, but enough that it's starting to show signs it's dying by possibly sending a low signal back to the PCM.
 
hitman92499 said:
No SES light I assume. I looked through a bunch of TSB's. I found on stating you could have a faulty MAF...not faulty enough to set a light, but enough that it's starting to show signs it's dying by possibly sending a low signal back to the PCM.
Click to expand...

No ses light but I'll check later for pending codes... I did forget to mention that sometimes under load I can have a slightly jumpy rpm, especially around like 2-2.5k rpm up hill. I can feel it jumping and see it on the tach
 
Seems like a PCM calibration issue, there's a TSB for it, Reference number 04-06-04-078 , it basically says the tcc stays applied during light throttle application, the new calibration addresses this concern.
 
Sounds like a very similar problem that I had. It ended up being my torque converter. The problem went away right away when replaced but I did notice that my TC likes to engage when I go as slow as 30 mph.
 
So last night, I got some surging and jumping rpms, jumping maybe 200 rpm with each surge, again with light to medium throttle... only doin about 35-40mph, and sometimes it has a really really minor stumble or cough on starting, like it cranks, coughs and sputters for less than a second and starts.. it only failed to start once and I had to hit the key again.. then it started.

Sometimes when this surging and jumpy rpm is happening, it feels like the car wants to get up and take off, but then it decides to cut back at the last second, or it wants to shift but then it decides not to.

I finally got an SES light but it's for catalyst inefficiency, and I have a zzp downpipe so that's not surprising considering the car isnt running right, no other codes.

I think Im going to try to disconnect the battery over night tonight and see if that maybe resets the tranny shift behavior to help, if that doesnt work... If you guys think I should replace the MAF I'll try that, otherwise Im going to be buying a tune in the next month so I'll just wait for that then and hopefully it'll fix this calibration issue some of you talked about.
 


I've had almost exactly the same issues with my car for the past 2 years. I've never really dug into it because it hasn't really changed. I've had a friend scan it with HPTuners as we drove and nothing irregular shows up. It seems to go into lockup early, then when you want to accelerate, it doesn't want to unlock until you jab the throttle hard enough to make it downshift.

After some recent events, I can tell you that replacing the MAF had no effect on this problem for me. I blew a vacuum line after some heavy acceleration and shortly after, the MAF died.

I've suspected for some time that it's a bad PCS or TCC solenoid. My usual mechanic doesn't do transmission work, so I've been avoiding taking it elsewhere because I'm broke. I could probably tackle this job myself, but I just haven't had the ambition.

I'd be interested to see what effect a tuned PCM would have on this problem. I've been considering getting one to see if the increased line pressure would help.

I should also note, over the 2 years, this problem seems to get better or worse with the weather oddly enough. When it's cold (especially in the winter), everything seems to work great. It often shifts as it should normally. In particularly hot and humid weather (90F+) it gets worse. I had one day last year where it was about 95F and was shifting very hard. It shuddered up a couple of hills and I wasn't sure I was going to make it home, but I did. The next day was around 70F and much less humid and it was fine. It still stuck in lockup but there was no hard shifting or shuddering.
 
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Was thinking and have some new details..

when I'm in park and idling and I rev it up to say 3k and let off, the rpms drop way down below idle speed then back up a little above idle speed, then drop back down below etc and then slowly evens out.

Also yesterday was the first time it bogged under heavy throttle, I was passing a friend on the interstate and wanted to make the blower yell at him so I hit it and it downshifted nice and I took off, but then right around 3k it felt like someone reached their foot over and pressed my brake pedal for a second, no drop in rpm just power cut out... I think even boost stayed up. It was only for like 2 seconds and I was going again.. Power came back gently though, not neck snapping.

Kinda hoping it's the Maf or PCM at this point and not needing tranny work lol
 
SO... Today I was driving along like normal and around 35 mph, light throttle still accelerating from a stop light leaving town, the road starts to go up hill a little so I leaned on the pedal a little more, got to about 2.5k rpm and the car started bucking and surging so bad the gf and I were jerking out of our seats.

I let off the gas and babied it for a little, but had to get up another hill so I had no choice and again it felt like the motor was gunna break apart.

Stopped at the next traffic light, got the arrow to make the left and I pulled out... went slow cause it's a sharp left and there was traffic behind me going faster than I was so I wanted to pick it up a little, gave it some throttle and I got 0 response, got pissed and pushed the pedal just a bit more and the car jerked and took off so hard, blower whine and put us back in the seat and everything. So that was the line, I said the second we get where we're going, Im ripping that MAF out of there.

Got to our destination and I just totally unplugged the MAF and threw it in the back seat.

Car now drives like a dream, lol. Eaiser starts, no more hesitation, no more jerking and chugging, no more complete lack of power, and my instant mpg read out is showing a little higher than average... I really hope I found my issue here and the probably didnt just go into hibernation like it sometimes does.
 
Put in the new MAF today, seems like everything is good now.. shifting is great, power is great, no more hesitation or choking on start up.

So now I buy my Aeroforce!
 
That's good news. Disappointing for me... lol. I was hoping you were going to do all the troubleshooting and find a solution that could fix my issues as well. I guess I'll have to get off my lazy butt and figure it out myself.
 


Well, the issue has returned. It drove good on the way home but a few hours later it took it out again and it started bucking and surging again. I was so pissed. I unplugged the sensor again and it ran good again, smooth as butter, power on demand.
Plugged the sensor in again and right back to crap.

So the only thing I can think of at this point is to return this cheap reman one and get a OEM Delphi replacement.

I mean 100% of the problem is tied to having the Maf plugged or unplugged, so it has to be the sensor, right?
 
Replaced the Maf again with another reman one and it worked for 2 days, everything was great. Then it just started up again this morning. I unplugged the Maf and unhooked the battery, touched the 2 terminals together like I read to do on here to reset the PCM. Had a decent drive today and things seem to have iimproved again for the time being.

I just want my car to drive right again, the past 2 days were awesome I looked forward to driving my car again instead of being aggravated with it.
 
So like... how could it be that it was running great with the new sensor for 2 days and then suddenly right back to where we started?

The problem isnt AS bad as it was with the bucking and surging, but still have the lack of power, refusing to shift without hard throttle.
 
Since the thing is running good in speed density I would guess wiring since it was running well in mass with the current tune.
Remove the wire shielding for all of the 5 volt referened sensors and make sure conductors aren't shorted or corroded.
It could be something as simple as the return signal wire from the MAF back to the PCM.
 
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