spectre86

Went to a smaller dealership after calling them. The car was already warmed up and running when I pulled in. Looked clean, got in it to go for a test drive. Shut the car off and turned it back on.

Heres where the problem(s) happen.

The RPMs kept bouncing from 1000-1800 pretty bad. It lasted for about 5-10 seconds then leveled out at about 1000-1100rpms.
I pull out on to the road and gently roll into it(normally, not aggressive). The car starts cutting out.. Almost like it hits a wall. Bad, to the point its bucking bad like when you get in a car with a manual trans and a woman driver. lol
it bucked bad. This was at about 3000 rpms at MAYBE half throttle?

Pulled back in and got the "its never done that before" line from the dealer.
He told me "these cars are known for full pumps going out"

He said he would take it to the GM dealership and have them try to figure it out. and call me in a day or 2. I walked out.


Any ideas guys? Im buying this for a DD, so I really dont want another persons headache.

its a 1 owner, 66k mile car. Looks to be completely stock. it was a repo and he bought it at an auction. I ran the car fax and hes had the car on his lot for going on 3 months.


Any ideas what it could be? not in the mood for someone elses headache

~Mike~

iTrader: (2)

Refer to the other thread you have going about this lol

It's the throttle body is gummed up and dirty with crap. The bouncing idle, cobalt problem. Lemme guess, you noticed this extreme bouncing after or as you were coming to a stop? And it almost felt like it was going to die out before it went all bouncy?

spectre86

actually it happens right at take off. I honestly dont think I got above 30mph. I COULDNT, the car wouldnt accel.

~Mike~

iTrader: (2)

sounds like the TB to me, if it were anything else, you'd prolly hear it in the way the engine runs.

rnjmur

I say have them take it to the dealer to get checked out. It may have had a stage kit on it and never got tuned back to stock. Could be a throttle body problem. Was the boost guage really bouncy when the idle was having trouble as well? It could have a leak in the intake somewhere if the previous owner swapped back from a aftermarket intake and didn't get it sealed up right, or if the MAF was damaged.

If they take it to a dealership, find out which dealership they took it to and make sure you go talk to the dealership to make sure everything is kosher. Those small auto dealers are more times than not, a bunch of crooks.

I have never heard of cobalts being notorious for having fuel pumps go out, so that was just some BS line they fed you.

spectre86

Wow, crazyness. I would have NEVER guess a throttle body would cause symptoms like that.

Maybe ill give it another try. It was an hour away, so Ill wait a day or 2 and maybe hear back from the dealer. Hes had it for about 3 months and theres no way someone would buy it the way it was running.

ItalianJoe1

iTrader: (10)

it's not just a throttle body if it's doing that much.

Bad MAF is my guess.

StreetDreamz

Mass airflow sensor. Also, check to make sure there are green top injectors (stock) installed. If they aren't then the car probably has a shitty tune on it with some larger than stock injectors. Even the "greatest tuners in the world" (such as WickedSS2005 on here) sometimes don't know how to properly tune larger injectors. Could also be the cam position sensor. The fact that they had the car already warmed up for you means it has problems with cold starts too. This points me toward cam sensor or SERIOUS spark plug fouling/bad coil pack/crank sensor.

spectre86

Wouldnt a MAF set a check engine light? There wasnt a check engine light on .

SuperchargedSS

HAhaha you have my old SC!


Seriously dude its a MAF problem, you're ok. They dont throw codes 90% of the time . I went through a couple on my sc. PM Me I can save you. I know how to make the sc butter smooth.

DOes it still have my corsa on it?

StreetDreamz

Not always. Sometimes it will take a steady state cruise with a bad MAS to set a CEL. Of course, the dealer could have cleared it out seconds before you arrived with the hopes that it wouldn't come back on while you were test driving lol.

SSchargedSS

no you only get a light when **** is bad lol I think its like 25% fluctuation until it goes on./. so things can still not be right even without a cel

very well could be the maf

~Mike~

iTrader: (2)

I'm so bad at this....are you being serious? lol

spectre86

I dont think so unless your car was repoed? Its got a pioneer sub on the side pannel of the trunk and tinted windows. The exhaust looked and sounded stock.So the dirty throttle body and MAF going out are common problems with this car? Whats the cost of a new MAF from gm?

My concern is I dont want it to be something like a ringland starting to come apart

SuperchargedSS

Well, my sc had this exact same problem many times and I have fixed it on a couple others. Bring it to a dealership and have them test the maf. Trust me you wont always get a code. Does it feel like it stops accelerating when you press the pedal down a bit, and then buck when you get off it?

New maf + install up here is 350$ if you go through a dealership. SC's have been pilling up in salvage yards (many with the css.net sticker still in tact) though so I would go that route.

spectre86

many times? you went through a few MAFs? or had to clean the throttle body a few times.

yeah it stops accelerating because it feels like its running lean and hitting the rev limiter.

Is the MAF the same on all cobalts or just the SS?

SSchargedSS

dude you can get used MAF's doing a google shopping search for 25 bucks, with warranty. (last i looked)
and its cake to install. Dirty throttle body is common. Think its the oil vapor that feeds back into the intake tube doing it. Clean the throttle body is easy, so do the easy cheap things first.

spectre86

Well I havent bought the car yet. Still in talks with the dealer. He called me yesterday saying the car was at the dealership and they are replacing the fuel pump/filter. I mentioned to him about the throttle body and he said they already checked it and its not the problem.

No idea if he is telling the truth or not. He said it was like $800 and something for the cost of everything including install. I guess Ill hear more either today or monday.

I have a feeling that he is going to try to use this as a reason to stay firm on the price.

constantproject

no..that would be a reason to come down a bit in price, unfortunately for them you knew it wasnt to par and called them on it, you could prolly get alot more off if you hint at reporting them to bbb lol

a fuel filter could cause some symptoms like that but it sounds like there might be an intake leak, and i think the bouncing is just a cobalt thing my 2.2 does it to some extent

spectre86

No I ment after he got the parts replaced. Whats "bbb"? Its a small independent dealer, not a major chain or anything. Oregon has a buy or beware law.

He knew there was a problem. Thats why hes had it for almost 3 months and thats why the car was running before I pulled in. Ofcourse hes going to say " it has never done that before and I would never sell a bad car"

It was funny though, there was a couple that were test driving an early 00 jag that he had on the lot. We both pulled in at the same time and he was complaining the check engine light came on during the test drive.