Hi. I'd like to know why my 03 SS can't idle. It can idle for like 5 seconds when it starts cold but when it gets below 1k RPM it bogs and dies. Prior, a P0101 code (MAF out of range) tripped and it would idle at 2k. i cleared it and now that's where I am now. the long fuel trim is docked at -25 (probably the end of the range of which my reader can read). I've left the battery off overnight but it didn't change anything. The filter is clean and there isn't any visible damage to the throttle body. Also something that may be related, the engine makes an extremely loud, constant noise that comes from the intake. This seems to happen only when the engine is cold and it has been amplified because of this idling problem. Any help would be appreciated!

 

Sounds like your MAF is bad to me.

 

Yea sounds like my favorite thing in the world, the 3800's mass air meter! You said you cleared the code, did you fix the problem first? Sometimes using maf cleaner just fixes it for a short period of time. If its not the maf, its likely one of the sensors on the throttle body.

Also, that constant noise is the idle air control valve. Totally normal.

Funny story, when I bought my bonneville the seller thought something was wrong with it because of that noise and I got $1000 off to "take a chance with it".

You could unplug the maf and see if that fixes the issue. If the problem goes away, thats the problem.

 

Did you repair anything to try to fix the reason behind the code or did you just clear it?

If you didnt actually fix anything, I'd start with what Chibi said- MAF. It's easy enough to check, just unplug it. If the engine goes back to normal running off MAP only, then you know it's as simple as replacing the MAF.

Since it sounds like you've got a scan tool, you could also check it by reading the MAF frequency.

If its not MAF, you need to hook the scan tool back up and gather more data on the key sensors when its having the issue.

It's the limit of the pcm, not the reader. Theres only so much adjustment the pcm allows as normal and when you get to / past a point like this, something is clearly very wrong that it cant correct on it's own.

This is also consistent with a MAF issue though, but certainly could be other things as well.

TBH, that's kind of a strange diagnostic method.

Probably IAC going nuts trying to keep the engine alive. Kind of in vain though if fuel trims are that far out of whack though.

 

i actually didn't know it could run without the MAF. i'll try that later and see if it works without it. i left the battery off because i thought it would reset the computer, i thought it was worth a try.

 

Thats only if you cant clear codes, which it looks like you can

 

And even then, theres no reason to clear them until you've made a change that you think resolved the problem.

 

Ok so I got a new MAF sensor and it seemed to work for a minute (after being rough) and then it started being rough again. then it started to bog heavily and now it cant start anymore. ive left the battery off of it hoping itll do something along the line of fixing it.

 

Check fuel pressure and for vacuum leaks

 

I take it you did as we noted above, unplugged the MAF sensor and then it ran fine to prove the MAF was bad? If so, unplug the MAF again, and take the new one back for an exchange. If you bought a cheap MAF, it could be bad out of the box. If a new quality MAF does the same, then the issue could be elsewhere in the MAF circuit (wiring, pcm).

As long as it runs fine on MAP only with the MAF unplugged, that pretty much rules out any other issues.

I'd also not bother with continuing to unplug the battery, that doesnt fix anything. All it does is reset codes and fuel trims, it won't repair any actual issues.