cibrlx01

Has anyone else had these issues? (Drive-ability Concerns)

I am wondering if anyone else has had a couple of these issues so that i can help the dealership find these issues.
Dealership couldn't replicate either issue.

Car is 2009 XFE lower trim w/ 155hp engine

Main 2 issues - Drive ability Concern
Intermittent - when car comes on after standing in cold for few hours, tachometer goes +500 RPM and than -500 RPM, than does it again for a few times until evening out.
Ironically, this happened right after i picked car up from dealership, (so i guess car was sitting for around 5 hours or more. Also happens sometimes in morning. After it happens once, it does not reappear for a while, multiple starts, but it usually does come back.

I think 2nd issue is related.
Engine hesitates during acceleration mostly on upward slope. My car is standard so it usually happens around 3.5k RPM but i have seen it happen between 2.5k RPM and 4.5k RPM. I have also seen this happen on an upward slope and a flat slope when i accelerate onto the freeway.

Oil was changed 1000 - 500 miles ago. mileage as stands is 17,000ish.

mostly happens here on this route

Sir Francis Drake Blvd to Unknown road - Google Maps

on following uphill slope after driving for 5 minutes

Sir Francis Drake Blvd to Unknown road - Google Maps


Thanks for any help
-Alex

cibrlx01

also, while my main concern is the drive-ability issues stated above,
my car's history is as follows

around 3k miles fuel pump failed and was replaced

around 4.5k miles shift link assembly was replaced, wasn't entering 5th gear, may or may not have not been entering 4th gear

recently, lets say 16,500 miles, windshield was replaced because of major leak coming from D.S. B-Pillar
F.P. Headlight replaced because of condensation
Rear Center Brake light was loose, inside nut unscrewed itself? this just tightened back up

17k miles key stuck in ignition on ac on position. Luckily i got her home that day. Battery was dead next morning, jump started from friends car, took to dealership.

Right now: (17k & 150 miles)
Also, I have a rattle from passenger side (might be glove box)
Also, Aux Input Jack is loose, does not go to aux station when cable is put in
Also, Front Passenger speaker makes door vibrate... took to dealership, they said its not an issue, its caused by settings being too high, and that i need to adjust them for different songs, bass, treble, mid, are in middle ...

cibrlx01

saw 2 posts on *************, 2 posts so far stating my problem about cobalt reving up and down. One guy said that his car got fixed by the replacing crankshaft sensor.

Can anyone confirm issues with crankshaft sensor and tachometer reving up and down?

Jaredssbalt

iTrader: (4)

My car does same thing sometimes. I heard that on mine it was due to my bigger injectors. Something about the engine trying compensate by adding more fuel (causing rpms to raise) and then taking away fuel after addin more to compensate for the raised rpms, causing the rpms to drop. This repeats until the car finally levels out the rpms. As for the uphill problem I have no idea.

The rpm thing is just one of the cobalt things you have to deal with. I wouldnt worry to much about it, but the hill thing you might wanna look into. The rest of the things you mentioned too like the key getting stuck are just some of the gr8 things about having a cobalt lol.

Jeffs 06SS 2.4

I have had a bad throttle position sensor do that on an old mustang and also my ex girlfreinds doge neon. Both were bad throttle position sensor.

cibrlx01

also, i feel like my mileage has been mid 20's (around 26-28) on an xfe with mostly highway driving
would a bad throttle position sensor cause this?

kikal8

iTrader: (1)

alright. so the only thing i can help you with is the reving. my car does the same thing. usually right when i start the car and its still warming up after you rev it or park the idle revs up then down and gets smaller revs until it evens out and stops. if your xfe has a throttle body instead of a regular throttle its pretty normal for throttle bodys to do that. i wouldnt worry about it, ive seen cars do that and everyone says it normal. my brother whos a mechanic also says its normal for a throttle body to cause that. idk y really. but its just even out the air flow. like idk. but from what i have heard thats normal and ive had that happening since ive got my car so..

Kolt

i have the same car u do but a 08 and it does the same thing with the rev's, never figured out why it does it. its just a cobalt thing. also the hesitation may be to your throttle body being dirty. the crankcase breather crap tends to suck oil into the intake. I take this from personal experiance bc ive had to clean it 2wice since i have had the car and im at 38k miles. i stuck a filter on the valve cover for the crank case vent and a rubber cap on the intake and havent had any problems since 25k miles. as far as the rattles. thats a cobalt for ya. just gotta hunt them down and slap tape or dynomat on it and call it a day

CanadianCobalt

iTrader: (5)

Let's talk Idle bounce haha.

https://www.cobaltss.net/forums/2-0l...inally-116051/

Mine is my tune from having 60's, it only does it in cold weather and hopefully will be gone once I go trifecta or something. But a lot of LSJ's have used this to fix theirs. Not sure if it will carry over to the LAP/L61/Whatever is in your car. But it's worth a shot.

Joel