So yesterday I drove to my girlfriend house (15 minute drive) and my 2.4 Cobalt SS (2006) drove fine the whole way. I parked it at her house, went inside for roughly an hour or two and came back out. Car started fine, drove into the local town and started having trouble accelerating. Every time I would accelerate (not really hard, but harder than granny) the car would misfire like crazy (like a machine gun outta my fart can).

It shot off a couple codes when I read it while driving, something to do with MAF, a random misfire code, and some other + p0068 but when I shut off the only code that stuck was the p0068 code. That said, started it up today to pull it in the driveway to investigate and it acted fine. So nevertheless I pulled apart the intake, removed everything, cleaned the MAF, cleaned the throttle plate, put it all together and made sure everything was nice and tight. Drove real nice and pulled just fine for about ten minutes so I went down to the car wash pleased.

When I started it up again to leave, it revved up to 3k right off the bat without me doing anything, then dropped. Shut it off again, started it again did the same thing. Then while driving down the road it started doing the exact same misfire thing under hard accel. Could it be something as simple as my plugs?

What should my plugs be gapped to with a 2.4?

Anybody have any experience with this? I have a sketchy coil pack (it came apart when pulling it off the plug, but I put it back together) could it be that too?

It's just odd to me that it only does it when it's warm but pulls fine when cold.

Thoughts?

 

Okay random update. Just for the heck of it I went outside to compare with maf plugged in and without maf plugged in.

Car wouldn't start with, or without maf plugged in. So now I can't even start the bastard! What the hell?

 

I hope u still had good sex at ur gf's house... Sucks to leave the house when u had no sex AND ur car runs bad.


Seriously now, I had the same thing on my coby and it was a wire that was stretched in the plug of the MAF sensor.

 

Hey thanks for the post. I'll take a look at the wire, it seems fine but I'll look anyway. It could have something to do with it, yesterday while driving home I lost all power and stalled out. I popped the hood, wiggled the maf sensor wires + plug and started it back up and drove home. So I don't know.

Anyone else have any advice? I'd love to get to work tomorrow! Money is good.

Would something wrong with the MAF cause it to rev to 3k like that off the start?

EDIT: Went outside, didn't mess with the wires yet but gave it another go anyway (MAF plugged in) and it started, but rev'd to 3k again and idled a little funny, and kind of surged.

Any ideas?

 

Another update: Went outside, wiggled the wires to no avail. Car acted the exact same, although this time when I started it, it did not rev to 3k.

I unhooked the MAF - car would not start
I hooked the MAF back in - started, took for a drive and did the same thing
I unhooked the MAF while car was running - ran for about 15 seconds, then stalled out and wouldn't start

I'm thinking the MAF is not the problem?

EDIT: Should I be unhooking the battery in between, and seeing if the condition reoccurs after the ECU relearns? It seems that when I unhook the battery for a couple minutes and hook it back up it runs fine for a little while, then goes back to it's problem... which makes me think it's learning from the MAF which is sending the wrong info?

Not sure guys. Need help!

 

That don't sound good, maybe that's your problem? Just a guess. What did it say the codes were that it threw?

 

Thanks for buying from GM! There's lots and lots of fine print describing everything that will go wrong with your car, but you won't figure out that we decided NOT to give the small brochure until a tenth of a mile after your warranty expires.

Definition:
coˇbalt (kbôlt)
n.

A ticking time bomb.

 

It just doesn't make sense to me that it runs fine if you disconnect the battery, (AKA reset the ECU) for a while and then goes bad. I'll have to try that tomorrow as it's late here just to verify, but that's what it's been doing as far as I know.

If it was the coil pack it would misfire consistently, no?

P0064
P0300


Something else that had to do with MAF - couldn't remember what it was (it only showed when driving), I only have a cheap little scanner and it only shows one code (p0068), but actually that code is gone now because I reset the battery/ecu and it hasn't tripped a CEL even though I've driven it around with this condition here for probably 25 minutes today total.

I THINK I had " P0101 Mass or Volume Air Flow Circuit Range/Performance Problem" just going by what I remember though.

It's weird how the CEL isn't on even though this issue is so apparent.

 

Lol no kidding! I love my balt, but I really don't want all these issues. >.>

 

P0084 Exhaust Valve Control Solenoid Circuit (Bank 2)

P0300 Random/Multiple Cylinder Misfire Detected

looks like it could be your solenoid and not actually ur maf, but the malfunction in the solenoid perhaps causing maf to go screwy.

 

Sorry, I wrote the wrong code:

p0068

Is the code I had

P0068 - Throttle Position Sensor Inconsistent with the Mass Air Flow Sensor

Might I also note that after a while of driving like this home from my GF's, the car went into Eng. Pwr Reduced mode AKA limp.

I get no power, it doesn't just misfire, I don't accelerate at all. It feels like if I hold it the car will just stall out.

 

P0068 Throttle Body Airflow Performance ECM, PCM

if it were your maf you'd probably get this: P0101 Mass Air Flow (MAF) Sensor Performance ECM, PCM

sounds like u just need to fix the throttle position sensor. i'm not sure if that can be fixed or u need a new TB. I'll let someone else answer that.

 

I do believe I had that code.

If it was the throttle body sensor, would it cause it to misfire too though?

 

disconnect battery, unplug throttle body, replug throttle body, connect battery. see what happens

 

Will try that when I get home!

 

Another update - started up fine today when I got home from work. Took it out for a drive, ran it until it was at full operating temperature, pulled fine and seems like the issue is gone? Maybe it has something to do with moisture? Will reply back with any further updates.

 

Okay - so took it out again to test my theory, seems as though if it's bone cold it runs fine until you let it cool off again. When I tried to take it out again, same thing happened. Revved to 3500RPM, started surging kinda.

It was actually accelerating on it's own this time, which leads me to think throttle position sensor again. I unhooked the wire and plugged back in and it had no effect.

Any ideas?

Codes were (looked up on women's phone)
P0068
P0101
P0300

No codes set by any of this by the way. PS - WTF CHEVY, why the electronic throttle system. >.>

 

Weird, I unplugged the battery today and let it reset and it's been fine since. Maybe it had to do with my cleaning of the TB, guess I should've unhooked the battery while doing that?

 

yes...

 

I'd go with that