Flutter in idle; serious hesitation

comanche · 04-16-2007, 09:53 PM

99' Olds Alero 3.4L
(engine recently replaced, sold as 22k)

Idle when started flutters about 500 rpm back and forth 3-4 times.
Severe hesitation on acceleration (not all the time, usually after a couple minutes driving and most often after turning a corner)
New plugs, plug wires, fuel filter, air filter (also tried WAI)
Different EGR valve, MAP sensor, ignition module
Fuel injector cleaner run through multiple times
Vaccum lines checked, electrical connections cleaned.

Hesitation so severe at times it can be unsafe when trying to turn in front of oncoming traffic. Any ideas??

cavaliers60 · 04-16-2007, 09:55 PM

you might have water leaking in somewhere.... I know my car did stuff like that when I got water IN the engine a couple times... Thank God it didn't hurt it... But yeah, sounds like something's leaking.... Might be a LIMG thing gone unfixed...

SweetNLow · 04-16-2007, 10:15 PM

o2 sensor

antichrysler · 04-16-2007, 11:37 PM

^ agreed.

Wouldn't hurt to try some condensation remover either in the gas tank.

Cliff8928 · 04-17-2007, 02:18 AM

Were the old fuel injectors re-installed back onto the new engine?

comanche · 04-17-2007, 09:59 AM

Yeah, old fuel injecters were reinstalled. (the engine was a 00' so I had to switch out the injectors and harness.)

Which 02 sensor?

Redog · 04-17-2007, 10:08 AM

Most likey a downstream, but replacing both wouldn't hurt

Is the MAP plugged in all the way

jackal2000 · 04-17-2007, 03:44 PM

Quote:

Originally Posted by Redog

Most likey a downstream, but replacing both wouldn't hurt

no way is it the downstream sensor because all that sensor does is check to make sure the cat converter is working. that being said, if this problem is caused by an o2 then its the upstream one. they run about $85.

Gr1m · 04-17-2007, 10:17 AM

get a voltmeter and check the o2 sensor pigtail after uve replaced it

comanche · 04-17-2007, 12:48 PM

MAP appears to be plugged in fully - Why? (The connector tab broke, but i taped the plugs together really good.
What exactly am I looking for on the voltmeter?

Redog · 04-17-2007, 08:22 PM

Quote:

Originally Posted by comanche

MAP appears to be plugged in fully - Why? (The connector tab broke, but i taped the plugs together really good.
What exactly am I looking for on the voltmeter?

I left mine unpluged once by accident and the car was revving from 500 to 1200 at idle

jackal2000 · 04-17-2007, 03:43 PM

scan it for codes, not all codes set a MIL. i would clean the throttle body and change the tps too.

comanche · 04-17-2007, 07:06 PM

Took it to the dealer, talked to a friendly tech:
Test-drove it with the tech2, he said start with the MAF sensor, also clean the IAC.
Replaced the MAF with a rebuilt one, cleaned the IAC = no bouncy idle yet, but the hesitation is still the same.
He said it looked like the 02 sensor was good, & doing what it was supposed to.
It didn't cost anything at the dealer, but $106 w/tax for the unneccessary MAF kinda' hurts.

comanche · 04-17-2007, 07:06 PM

I did also put in a bottle of gasline antifreeze.

Gr1m · 04-17-2007, 08:39 PM

IAT sensor/pigtail...the car isnt throwing any codes?

Jferg2223 · 04-18-2007, 09:11 AM

when my limg went it started doing that until the car got warm

comanche · 04-18-2007, 10:33 AM

This car only does once warmed up about 3-4 minutes.

At least the idle is fine now (so far) - replaced IAC sensor.

The only code is the system rich code.

Jferg2223 · 04-19-2007, 12:19 AM

Quote:

Originally Posted by comanche

This car only does once warmed up about 3-4 minutes.

At least the idle is fine now (so far) - replaced IAC sensor.

The only code is the system rich code.

sounds like maf i think you mentioned a "rebuilt one" being put on if im not mistaken but thats the problem

comanche · 04-19-2007, 06:44 PM

Well, it looks like the LIM gasket is leaking. I'll start with that and see if the issue resolves itself.

comanche · 04-23-2007, 09:54 AM

LIM gasket replaced, same old problem just as bad!