I noticed this starting Monday.

Impy SS 2007 with 46,000 miles

When driving at light to normal acceleration, mainly when cruising on the highway or going up a hill, when i try to increase speed, my RPMs seem to not move unless i give it a big push on the pedal. The car does pick up speed when it doing this but the RPMS dont move unless i really increase the throttle then it takes off. Like it will jump maybe 200-500rpms and then drop back to where it started at until i put more force on my gas pedal to drop the gear.

Using the hill for example when going up the hill. I am doing 40mph at about 1500rpms. When i want to increase the speed, i push down a little bit on the accelerator and the car picks up speed a little but the rpms jump to maybe 2000 then slowly drop back to 1500. The engine sounds like you are trying to go up a hill when in 6th gear. I have to really push on the pedal (almost more then 50 percent of the way) to actually get it to kick down a gear and make the rpms jump like they should. Its never done this before

When it is doing this, there is no slipping, clunking, or hard shifts.. There is some slight hesitation when going up the hill but that probably b/c its trying to push this heavy load up with only 1500rpms of power. Sometimes i get the rotten egg smell but i think it does that b/c dumping a lot of fuel into the engine with only 1500rpms of power and the cat burning off the excess fuel?

I have cleaned the MAF thinking it could be a problem and still the same.. Seems to only do it once it warms up. Any suggestions?

 

i have a 98 ws6 and its doing the same thing right now..i gave it a tuneup and it didnt work..next i think im gonna clean the fuel injectors..its gotta be somethin with fuel..fuel pump or somthing..idk..but im leaning toward dirty injectors...

 

Sounds like DOD to me, sometimes mine does this. Seems it doesn't want to disengage without having more than a certain throttle percentage increase.

 

May not be DOD. Seemed to me when my trans was on it's way out, it was acting the same way. Would not accelerate under a small amount of throttle, and would have to give it a good amount of throttle to do so.

Eventually when giving a small amount of throttle, the trans would grind and hum. A few weeks later I was calling TEP

Hope this isn't the problem with yours, best of luck

 

i hope its not the trans..that would suck..and wats DOD?

 

dod displacement on demand.. runs on half cylinders to save gas

 

ya mine seems to like, Bog, and idles rough it seems..like i said i hope aint takin a **** on me...but i think its the injectors..thats my guess anyway

 

Well took it to the dealer today just for a test drive only today.(its been very hot here all week in west chester, PA so everyone has clogged there schedule with AC repairs) My appointment is scheduled for monday aug 1st. He saw and felt the issue and said it could be anything, it could be the tranny, vacumm leak, dirty injectors, semi clogged cat. They will do all the test on august 1st.

@TheWarden - DOD is a feature on our LS4 cars that stops feeding fuel to 4 cylinders thus saving gas as they say. Its only a good feature if you drive highways everyday. If you are a city guy, it worthless.

Also on a side note. I asked my dealer about my CAI, throttle body spacer, and magnaflow with fear if the tranny needs to be replaced.. He said I will be fine. GM does ask about aftermarket parts but they actually leave the decision up to the dealerships. Thats why you see some ppl get a new tranny with these mods and some ppl on here say there warrenty was voided b/c of the mods. Its all the dealership, so if that happens, go to another one. He told me those mods are not enough to blow a tranny. The mainly void warrentys if they find nitrous, tune, turbo / supercharger. Overall, if you are worried about your mods, call you dealership and ask..

 

I have the exact same problem as the first one you listed.

I get code P0700 every now and then, which is tranny, forget what the actual code is....But everyone else who got it needed a new TCC Solenoid, or a new torque converter...Or both.

Im guessing this is the problem you have based on what you said, but im not an expert.

No I have not gotten it fixxed yet.

ETA: Also have the burning egg smell...Only after long drives, I dont think its related lol.

 

ya after u explained wat it was i knew that its only on newer cars..u can manually shut off basically half the cylinders

 

its actually does it on its on. I wish we could do it manually as i would leave it off. the computer reads the speed and throttle position and will switch the modes on its on. If you apply more pressure while in 4cyl mode, it will switch back to 8cyl

 

I've had the identical problem on my car. It's been that way for 14,000 miles. Really frustrating. :-(

 

ya if anybody takes it to a shop and gets it checked out..let me know what u figure out...cas i hate driivin my TA now because of it..it pisses me off

 

I know this thread about 2 months old but i think we finally have come to a conclusion on what been causing my car to bog under acceleration in 3rd / 4th gear.. I sent my car in for the third time in the past 2 months and they said i have a bad torque converter.

They said that they did test on it and found it that it was taking up to 15 secs to engage and disengaged at times which is not normal.. They currently have my car for 4-7 days due to this part taking time to arrive.. I get a 2010 Impala LT2 as a rental and man do i miss my car. This thing is slow.

It took me 3 times for the dealer to finally do a test on the TC and tranny. First attempt they said can not feel a problem, car is driving normal.. Second attempt i drove the tech and he spotted the problem but after 4 hours blammed my K&N intake for messing with the throttle... That pissed me off, i knew that was BS. So i removed my intake and reinstalled the stock airbox which what do you know, it still does it.. Third attempt i told them it still doing it with stock airbox and if its not fixed, i will look elsewhere and this time they finally do test on the TC.. I do not get why they just dont do test on them when you ask them too. They have to find the problem always first.