Car almost stalls and bounces back and forth

EBlend · 06-05-2007, 12:46 PM

Okay I am having an issue with my car. It will turn on and at times run fine, but almost all the time, when I idle, the engine will almost stall and bounce back and just keep going over and over again. It drops to just under 500rpm and then bounces back to 1000 and just keeps doing it repeately. Anyone have any idea what could be causing this? I will be replacing the sparkplugs today but i don't think that this is really an issue.

coupe · 06-05-2007, 01:23 PM

ALOT of people have this problem (myself included) and no one has ever found a fix.

onesexyga · 06-05-2007, 02:47 PM

Same thing happens to me. Especially when i start it warm, like after i get gas. Dips to 500 rpm, then bounces back up. I heard from someone it could be a maf sensor. Do you have a CAI?

Panacea · 06-05-2007, 03:02 PM

Don't know if it's the same problem I was having, but tap the gas and see if it settles the idle back to normal.

Sprucegagt · 06-05-2007, 03:20 PM

Vacuum leak/TPS/MAF any or all could be the culprit.

coupe · 06-05-2007, 04:10 PM

Quote:

Originally Posted by Sprucegagt

Vacuum leak/TPS/MAF any or all could be the culprit.

Yeah until you change all that with new parts and it still does it.
Ive replaced everything there is to replace and it never fixes it. It started doing it at 45K miles and has ever since.

If you run a search you will see alot of people have this problem and no one has found a fix.

What sucks even more.....it never throws a code.

EBlend · 06-05-2007, 04:14 PM

Quote:

Originally Posted by onesexyga

Same thing happens to me. Especially when i start it warm, like after i get gas. Dips to 500 rpm, then bounces back up. I heard from someone it could be a maf sensor. Do you have a CAI?

i don't have a cai anymore but did at one point. I heard from a buddy who used to work in a gm dealership that the oil used to grease up the k&n filters is very bad for 3400 sensors, but it seems the whole problem started happening after I took out my car out of parking last year and run some seafoam through it. Some people say that seafoam ruins your plugs so I will try to see if new plugs will do anything, but i am doubtful

coupe · 06-05-2007, 04:44 PM

Mine started doing it LOOOOOOONG before i modded it.

Sprucegagt · 06-06-2007, 06:41 AM

Quote:

Originally Posted by coupe

Yeah until you change all that with new parts and it still does it.
Ive replaced everything there is to replace and it never fixes it. It started doing it at 45K miles and has ever since.

If you run a search you will see alot of people have this problem and no one has found a fix.

What sucks even more.....it never throws a code.

Ever hook up a scanner, like Autotap, to monitor TPS voltage / Long Term Fuel Trim at idle? I'd like to help out more, but I've never had this problem unless I've caused it.

EBlend · 06-19-2007, 05:46 AM

So I replaced the plugs and thought the problem went away, until yesturday and it started doing it again. This is so frustrating. I am never buying a GM vehicle again unless its a high end one. I guess it is time to start replaceing everything peice by peice until I find what it causing the issue.

Sprucegagt · 06-19-2007, 06:26 AM

Quote:

Originally Posted by coupe

Yeah until you change all that with new parts and it still does it.
Ive replaced everything there is to replace and it never fixes it. It started doing it at 45K miles and has ever since.

If you run a search you will see alot of people have this problem and no one has found a fix.

What sucks even more.....it never throws a code.

Just a side note. But I have had brand new TPS sensors fail straight out of the box.

EBlend · 06-19-2007, 08:20 PM

I tested a few things today and still having the problem. Tested the TSP and that looked very good, just like the repair manual said, with proper voltages displayed and no variation and all that. There is a device that you can plug into your car and go for a drive and it records all of your sensor information, would this be beneficial for me to do and would that information help me pinpoint the problem?

Also, could a clogged cat converter possibly cause this?

Lab Rat · 06-20-2007, 05:23 AM

I replaced my cat about 2 months ago, still tries to die occasionally.

AmbrosiaCaress · 06-22-2007, 01:36 PM

My own 99 GAGT does this... Only when it is warm... like after getting gas (as a previous poster stated)... Sometimes the car actually does die, and starts hard, other times it just bounces low to normal, low to normal...

I had the TPS sensor replaced, no real change...

Gotta love GA's and their quirks...

andrewe77 · 06-23-2007, 11:18 PM

Mine does it occasionally. My humble engineering opinion is that the computer sometimes gets into a feedback loop with the IAC valve where it is overshooting the target RPM. It will continue to do this until the input to the loop is changed such as tapping the throttle or putting it into gear.

videoman · 06-23-2007, 11:28 PM

Freind had a similar issue. I took off the MAF cleaned it ( very carefully ) with some Qtips and reset the PCM. So far its been over 5000KMS and he hasn't had the issue return.

WeibSunder · 06-24-2007, 12:00 AM

The only time I've had this problem is when I tried putting gas in my GA while it was running. Other than that I haven't had this problem thank God.

onesexyga · 09-15-2007, 12:37 PM

Sorry to dig it up, but any updates on this? mine is getting worse. Doesnt just do it on restarts, just does it at idle.

ss88 · 09-15-2007, 04:05 PM

I have the same problem too... After a restart, like a short trip (or getting gas as you guys are saying) But I havn't found a solution. However, When I was running my engine and was in that kind of mood I was looking around and I thought I'd check my oil too. When I took the cap off the crankcase to add oil the rpm's dropped. Some sort of pressure difference within the engine must of caused this.

nickofcourse · 09-15-2007, 06:16 PM

when my fathers van was running really bad it was moisture that got into the spark plug module?

idk do our cars have a spark plug module?

06-05-2007, 12:46 PM	#1
EBlend GAGT - Senior Member Join Date: Aug 2002 Location: Calgary, AB Age: 37 Posts: 1,308	Car almost stalls and bounces back and forth Okay I am having an issue with my car. It will turn on and at times run fine, but almost all the time, when I idle, the engine will almost stall and bounce back and just keep going over and over again. It drops to just under 500rpm and then bounces back to 1000 and just keeps doing it repeately. Anyone have any idea what could be causing this? I will be replacing the sparkplugs today but i don't think that this is really an issue.

06-05-2007, 01:23 PM	#2
coupe lick it AKA: Rand Join Date: May 2003 Location: Grand Rapids, Mi Age: 40 Posts: 7,347 Vehicle: 99 GAGT/96 Z71/05 R6	ALOT of people have this problem (myself included) and no one has ever found a fix. __________________ CarDomain.com http://profile.myspace.com/index.cfm...endID=31690558 he has asserted his dominance over competing males with the loud masculine sound form his exaust system, Females searching for a potential mate will be driven away by weaker exaust systems and attracted to his SLP.

06-05-2007, 03:02 PM	#4
Panacea Mmmm Donuts. AKA: Macleod52 Join Date: Mar 2003 Location: Rock Island, IL Age: 40 Posts: 3,160 Vehicle: '09 Malibu LTZ	Don't know if it's the same problem I was having, but tap the gas and see if it settles the idle back to normal. __________________ "Never argue with idiots. They bring you down to their level, and beat you with experience."

06-05-2007, 03:20 PM	#5
Sprucegagt Schwartz Power! AKA: Andy Join Date: Aug 2002 Location: Ranson, WV Age: 46 Posts: 2,027 Vehicle: 2000 Grand Am GT	Vacuum leak/TPS/MAF any or all could be the culprit. __________________ 2000 Grand Am GT (some day it will be SC/T) Mods: alot

06-05-2007, 04:44 PM	#8
coupe lick it AKA: Rand Join Date: May 2003 Location: Grand Rapids, Mi Age: 40 Posts: 7,347 Vehicle: 99 GAGT/96 Z71/05 R6	Mine started doing it LOOOOOOONG before i modded it. __________________ CarDomain.com http://profile.myspace.com/index.cfm...endID=31690558 he has asserted his dominance over competing males with the loud masculine sound form his exaust system, Females searching for a potential mate will be driven away by weaker exaust systems and attracted to his SLP.

06-05-2007, 02:47 PM	#3
onesexyga onesexyfiero AKA: Kevin Join Date: Sep 2004 Location: Vermont/New Hampshire Age: 35 Posts: 1,534 Vehicle: 00 GAGT, 88 Fiero GT	Same thing happens to me. Especially when i start it warm, like after i get gas. Dips to 500 rpm, then bounces back up. I heard from someone it could be a maf sensor. Do you have a CAI?

06-19-2007, 05:46 AM	#10
EBlend GAGT - Senior Member Join Date: Aug 2002 Location: Calgary, AB Age: 37 Posts: 1,308	So I replaced the plugs and thought the problem went away, until yesturday and it started doing it again. This is so frustrating. I am never buying a GM vehicle again unless its a high end one. I guess it is time to start replaceing everything peice by peice until I find what it causing the issue.

06-19-2007, 08:20 PM	#12
EBlend GAGT - Senior Member Join Date: Aug 2002 Location: Calgary, AB Age: 37 Posts: 1,308	I tested a few things today and still having the problem. Tested the TSP and that looked very good, just like the repair manual said, with proper voltages displayed and no variation and all that. There is a device that you can plug into your car and go for a drive and it records all of your sensor information, would this be beneficial for me to do and would that information help me pinpoint the problem? Also, could a clogged cat converter possibly cause this?

06-20-2007, 05:23 AM	#13
Lab Rat Fear the Four AKA: Craig Join Date: Jul 2005 Location: Kenosha, Wi. Posts: 452 Vehicle: 2000 Grand Am SE	I replaced my cat about 2 months ago, still tries to die occasionally. __________________ Lab Rat Fear the Four

06-22-2007, 01:36 PM	#14
AmbrosiaCaress GAGT Driver Join Date: Feb 2006 Location: Boston Posts: 9 Vehicle: 1999 Grand Am GT Sedan	My own 99 GAGT does this... Only when it is warm... like after getting gas (as a previous poster stated)... Sometimes the car actually does die, and starts hard, other times it just bounces low to normal, low to normal... I had the TPS sensor replaced, no real change... Gotta love GA's and their quirks... __________________ Ambrosia (aka: Tammy) ~ I'm in love with my car, got a feel for my automobile ~ (Queen)

06-23-2007, 11:18 PM	#15
andrewe77 GAGT - Member AKA: Andrew Join Date: Apr 2003 Location: Blue Springs, MO Posts: 162 Vehicle: 2000 Grand Am GT Coupe	Mine does it occasionally. My humble engineering opinion is that the computer sometimes gets into a feedback loop with the IAC valve where it is overshooting the target RPM. It will continue to do this until the input to the loop is changed such as tapping the throttle or putting it into gear.

06-23-2007, 11:28 PM	#16
videoman I shoot people. AKA: Mr. President Join Date: Aug 2002 Location: Winnipeg - Cruise capital Posts: 336 Vehicle: 2002 Grand Am GT Coupe	Freind had a similar issue. I took off the MAF cleaned it ( very carefully ) with some Qtips and reset the PCM. So far its been over 5000KMS and he hasn't had the issue return. __________________ Shooting people since day 1! MGAC

06-24-2007, 12:00 AM	#17
WeibSunder Got Airway? AKA: Matt Join Date: Jul 2004 Location: Evergreen,NC Age: 36 Posts: 1,337 Vehicle: 06 Dodge Magnum	The only time I've had this problem is when I tried putting gas in my GA while it was running. Other than that I haven't had this problem thank God. __________________ Kenntnis ist Kraft Air goes in and out, blood goes round and round. Any variation in this, is a bad thing!

09-15-2007, 12:37 PM	#18
onesexyga onesexyfiero AKA: Kevin Join Date: Sep 2004 Location: Vermont/New Hampshire Age: 35 Posts: 1,534 Vehicle: 00 GAGT, 88 Fiero GT	Sorry to dig it up, but any updates on this? mine is getting worse. Doesnt just do it on restarts, just does it at idle.

09-15-2007, 04:05 PM	#19
ss88 GAGT - Newbie AKA: Simeon Join Date: Sep 2007 Location: Right Next Door Posts: 14 Vehicle: 1999 Grand Am GT SD	I have the same problem too... After a restart, like a short trip (or getting gas as you guys are saying) But I havn't found a solution. However, When I was running my engine and was in that kind of mood I was looking around and I thought I'd check my oil too. When I took the cap off the crankcase to add oil the rpm's dropped. Some sort of pressure difference within the engine must of caused this.

09-15-2007, 06:16 PM	#20
nickofcourse GAGT - Member AKA: Nick Join Date: Aug 2007 Location: cleveland ohio Posts: 346 Vehicle: 2004 grand am gt coupe	when my fathers van was running really bad it was moisture that got into the spark plug module? idk do our cars have a spark plug module?

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode