mentioned in my evap thread but I'm not so sure they are related anymore so starting a separate thread.

ok my weird symptoms are continuing and I am searching for other things to check.

to start the symptom is that when lightly accelerating the rpm'* will bounce UP and make the car surge, the car will continue to speed up like normal, in fact i often wind up doing 70mph while watching the car do this since it'* still speeding up the entire time. If I make the car downshift or let off the gas it stops and it doesn't do it under WOT or even under mid-high throttle just under normal light acceleration.

what I have checked:
most of my ignition is new (within 1-2 years) including plugs, wires and coils. i am planning a tune up and the plugs will be again

I swapped my tps out with a spare junkyard unit I had and bench tested the one that was in there, I found that it'* resistance was all crazy when holding the sensor steady at any point and thought I had found the problem, after installing the other one the car ran very weird, holding the gears til redline while driving normal and such. I came back removed the negative terminal on the battery and re-hooked it and the car ran normal. however the bouncing problem persisted.

I have inspected the vacuum lines in the engine bay and found nothing out of the ordinary

I had my cousin ride along with his obd computer scanner and we watched all the sensors and saw nothing odd, the new TPS was also reporting correctly we also took the opportunity to watch my fuel trims and they stayed mostly +5-10 and spiked at +14 under WOT

what I have not checked/replaced

my evap system is in trouble i have several codes in the computer setting the SES light all related to the evap

the o2 sensor, maf, iac, and pretty much anything else you could think of are all original

I noticed yesterday that my fuel pump (replaced before I joined the club with an airtex ) seems noisy I.E I could hear it over the motor on a cold startup outside the car

please any ideas or suggestions do not hesitate to post my goal is to get this thing completely tuned up so that I can install my zzp mps guilt free and this is problem #1 right now

if ya need the 2 purge valves for the evap system i have both of them

Does it happen to do this if your on cruise control and going down a slight incline, or up a slight hill? Wonder if you have a bad motor mount.

the front mount is new and the problem has spanned two mounts

after researching the 5 (yes 5!) evap codes in the DTC thread I have maybe it is related after all I have the following codes

P0440
P0446
P0452
P0453
P1441

My car (08 cobalt) is doing this same thing... the guy at the shop said it could be my purge valve in the tank... not sure tho... I'll need to find time to have it really checked out. The car is bad to idle weird & then just shut off too...

If the purge valve is bad it would be like a vacuum leak. Do you have any codes? Have the car scanned. Locate where the EVAP connects to the throttle body and pull the vacuum line off, then cap that off on both sides. This shuts off the EVAP system. If things calm down then you have a issue with the EVAP.

ok, thanks! I'll give that a try!... I had it scanned last weekend but my fiance didnt remember the codes (i was at work) It'* been doing this for a while now but never thru a CEL, I hit a rock one day (i'm too low & i should have know i couldnt have drove over it) and the rock hit hard under my car around the spare tire compartment. That same day the CEL came on, I may have hurt something there too... I'll let yall know what I find out!

It'* possible you hit the fuel tank. I would get it up on a lift or ramps and look around for the impact point.

well between the new o2 and evap purge solenoid I think my symptoms are cured. I haven't gotten to drive it much in that past few days so if it flairs up again I will update and continue investigating in case some other poor soul has to deal with this. also the solenoid seems to have cured all evap codes, P0452 popped up once since changing it but then went back off with the next crank so that might have just been a fluke