Hesitation off idle
07-03-2002, 05:35 PM
#61
Registered User
Join Date: May 2002
Location: Fort Wayne, IN
Posts: 119
I start my car after sitting overnight or at work for the day when it's hot outside - and then it starts and almost dies. It barely hangs on there for about 15 secs. Then it never really recovers fully until you get going down the road. When you rev. it up when it's like that it sorta just seems bogged down - letting you only get to say 4000 rpms and sounds real bad. I've replaced the EGR, plugs, wires, cleans MAF sensor, throttle body, air intake and i'm running out of things to change. The dealer says since it is intermittent they don't know what to do for me. What should I try next? Thanks
- 95 Camaro Z28 M6 w/ 109,000 mi
[This message has been edited by troywg (edited July 03, 2002).]
- 95 Camaro Z28 M6 w/ 109,000 mi
[This message has been edited by troywg (edited July 03, 2002).]
07-03-2002, 06:41 PM
#63
Registered User
Join Date: Jul 2002
Location: Hurlburt field, FL.
Posts: 140
Mine is doing the exact same thing. In the morning it stumbles and sputters. The RPM's go up and down and almost dies. Now it doesn't do it all the time, but enough. Mine just had a rebuild too it, and quite a bit of these sensors were changed. I'm going to try a fuel filter and maybe a TPS and let you all know. Later
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07-03-2002, 07:02 PM
#64
Guest
Posts: n/a
<font face="Verdana, Arial" size="2">Originally posted by cjksflorida:
Mine is doing the exact same thing. In the morning it stumbles and sputters. The RPM's go up and down and almost dies. Now it doesn't do it all the time, but enough. Mine just had a rebuild too it, and quite a bit of these sensors were changed. I'm going to try a fuel filter and maybe a TPS and let you all know. Later
</font>
Mine is doing the exact same thing. In the morning it stumbles and sputters. The RPM's go up and down and almost dies. Now it doesn't do it all the time, but enough. Mine just had a rebuild too it, and quite a bit of these sensors were changed. I'm going to try a fuel filter and maybe a TPS and let you all know. Later
</font>
I would check your EGR, I know some people have had trouble with theirs causing stumbles, and their cars starting to miss.
07-03-2002, 07:16 PM
#65
Registered User
Join Date: Jul 2002
Location: canada
Posts: 2
Just an idea. Buy the book Lemonaid. These cars are major under warranty that GM wont tell you unless you confront them. This concerns parts you buy as well.I live in Canada but Its a world best seller so Im sure you have it down there. Great book to look into.
07-03-2002, 08:57 PM
#66
Registered User
Join Date: Jul 2002
Location: Fincastle, VA, USA
Posts: 29
check the vacuum line that runs to the fuel pressure regulator... with some hondas(i know its somewhat different..) it causes stumbling and the idle to go up and down all the time after its heated up, because of a split or damaged hose.. just a thought!
07-05-2002, 03:53 PM
#67
Registered User
Join Date: Jul 2002
Location: Hurlburt field, FL.
Posts: 140
Well I just replaced my Fuel filter and it doesn't seem to have helped much. Now do I need to replace my EGR if I have removed all my emmision stuff (smog pump & lines,Cat,etc..) or do I just need to take it off?
second, If I wanted to change my FP regulator should I just go ahead and buy an adjustable, I realize it won't really help because of the computer making it's own adjustments or just buy another stock one?
second, If I wanted to change my FP regulator should I just go ahead and buy an adjustable, I realize it won't really help because of the computer making it's own adjustments or just buy another stock one?
07-05-2002, 04:13 PM
#68
Registered User
Join Date: Sep 2000
Location: Ottawa, Canada
Posts: 36
Quick question for you guys. Anyone with a stall converter or M6 that launches at 2500RPM+ getting hesitation? I know that if I launch from a dead stop at idle, it hesitates, if I dump/feather the clutch at 1500RPM+ it doesn't. Just a thought.
Seta
Seta
07-05-2002, 04:35 PM
#69
Registered User
Join Date: Aug 2001
Location: Springfield, MO
Posts: 71
I have the same problem. I didn't really have it before the new motor, but now it's very obvious. Once temps reach 200ish, it bogs off the line, then takes off at 2000ish rpms. It also starts alot harder now. It seems to start easier if I turn the key to "on" for 2 secs before starting...thinking fuel pump. I've got new plugs, wires, etc. I've got a list of things to try once I find some time. Keep me updated 
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James
95 Z28 M6
-355 forged 11:1 motor, 3.73 gears, Star spec II clutch, Port/Poished heads, CC305 Cam, 1.6RR's, Pacesetter headers and Y-pipe, 3" cutout, Pullies, Homemade CAI with K&N, Ported/Polished MAF, Blocked EGR, Throttle Body bypass, LT4 knock mod., Accel adjustable fuel pressure reg., Hypertech Power Programmer, Hurst short throw with short stick, Airlift air bag, LakeWood lower control arms, LakeWood adjustable panhard rod, 1999 corvette wheels with carbon fiber inserts, Silver badges, Nitrous Works Wet kit 125 shot
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James
95 Z28 M6
-355 forged 11:1 motor, 3.73 gears, Star spec II clutch, Port/Poished heads, CC305 Cam, 1.6RR's, Pacesetter headers and Y-pipe, 3" cutout, Pullies, Homemade CAI with K&N, Ported/Polished MAF, Blocked EGR, Throttle Body bypass, LT4 knock mod., Accel adjustable fuel pressure reg., Hypertech Power Programmer, Hurst short throw with short stick, Airlift air bag, LakeWood lower control arms, LakeWood adjustable panhard rod, 1999 corvette wheels with carbon fiber inserts, Silver badges, Nitrous Works Wet kit 125 shot
07-05-2002, 05:39 PM
#70
Registered User
Join Date: Aug 1999
Location: dallas
Posts: 19
Well, count me in as another victim of this problem.
I have been playing with the ignition system and looking for vacume leaks for about a year now. Did find some problems and fixed those, but still haveing problems with the hesitation.
The idea LT1Brutus had is interesting and i might try it out to see what happens. I believe that the ESC/IM is a solid state electronic device. Whenever electronics get hotter, they get noisier and less effecient. So moving it away from a known heat source and allowing better air circulation/cooling could help.
But, my problem i believe is fuel related, and i change my filters on a regular basis, barely ever got a light gray out of the dirty end
I did hook a fuel pressure guage up and noticed that the pressure dropped suddenly (10+ psi) when i blipped the throttle, not even breaking 2k rpm. So its another vote for FPR or Fuel Pump related problems
The thing is, their is no silver bullit to stopping this problem as it could be a number of things(fuel, ignition, vacume, sensor) and different from car to car. We just have to make some educated guesses on what is happening and what we can check and go from their.
I have been playing with the ignition system and looking for vacume leaks for about a year now. Did find some problems and fixed those, but still haveing problems with the hesitation.
The idea LT1Brutus had is interesting and i might try it out to see what happens. I believe that the ESC/IM is a solid state electronic device. Whenever electronics get hotter, they get noisier and less effecient. So moving it away from a known heat source and allowing better air circulation/cooling could help.
But, my problem i believe is fuel related, and i change my filters on a regular basis, barely ever got a light gray out of the dirty end
I did hook a fuel pressure guage up and noticed that the pressure dropped suddenly (10+ psi) when i blipped the throttle, not even breaking 2k rpm. So its another vote for FPR or Fuel Pump related problemsThe thing is, their is no silver bullit to stopping this problem as it could be a number of things(fuel, ignition, vacume, sensor) and different from car to car. We just have to make some educated guesses on what is happening and what we can check and go from their.
07-05-2002, 05:51 PM
#71
Registered User
Join Date: Mar 2002
Location: San Juan PR
Posts: 3,083
Well... I am still having the problem...
ICM was changed
Opti was changed
All cables send out 300O~1kHm of resistance...
The coil seems good...
But when the car gets warm... There is less spark... When you let it cool.. The sparks start again... I used my old stock coil and the same thing. I am still using the MSD 6BTM and the Jacobs coil...
Any suggestions????
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94B4C M6
Finishing project
Borla Competition--
AFR Heads
383 + Paxton Supercharger
ICM was changed
Opti was changed
All cables send out 300O~1kHm of resistance...
The coil seems good...
But when the car gets warm... There is less spark... When you let it cool.. The sparks start again... I used my old stock coil and the same thing. I am still using the MSD 6BTM and the Jacobs coil...
Any suggestions????
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94B4C M6
Finishing project
Borla Competition--
AFR Heads
383 + Paxton Supercharger
07-06-2002, 05:20 PM
#73
Registered User
Join Date: Oct 2001
Location: columbia, sc
Posts: 385
ok i'm in. i came searching for hestitation problem and found all u guys in the same boat. so far i've changed 02's twice (bosch first heard they were having problems went to ac/delco),changed fuel filter,changed fuel pump(not beacause of problem), coil is relocated due to blower(away from heat)running msd 6btm ign. one of us has got to hit it sooner or later.how many have fixed the problem by cleaning the maf sensor? how about egr?
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97' ram air ws6, ati 8#,edelbrock headers, msd ign.,3"flowmaster cat back, gutted cats,
12bolt moser 373,art carr a4, vig. stall,bmr torque arm & sf connectors, hal shocks
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97' ram air ws6, ati 8#,edelbrock headers, msd ign.,3"flowmaster cat back, gutted cats,
12bolt moser 373,art carr a4, vig. stall,bmr torque arm & sf connectors, hal shocks
07-06-2002, 05:27 PM
#74
Registered User
Join Date: Oct 2001
Location: columbia, sc
Posts: 385
tried to post this once here goes again. same problem here. new fuel pump, fuel filter,plugs , wires, coil is relocated away from heat, msd ignition 6btm, replaced o2's twice. still hesitating. someone surely has found the problem
thanks
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97' ram air ws6, ati 8#,edelbrock headers, msd ign.,3"flowmaster cat back, gutted cats,
12bolt moser 373,art carr a4, vig. stall,bmr torque arm & sf connectors, hal shocks
thanks
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97' ram air ws6, ati 8#,edelbrock headers, msd ign.,3"flowmaster cat back, gutted cats,
12bolt moser 373,art carr a4, vig. stall,bmr torque arm & sf connectors, hal shocks