I dunno if i should put this in the performance or mateniece but anyways. My gf's 98 sunfire gt has a very bad hesitation when accelerating usually when your going up hills. It doent do it at high rpm or anything about say 3000 but below that it stumbles and such and then takes off..any ideas? im thinking something in the ignition but i have no clue. We arent getting any cels or anything. phil
I have no idea if this is related to your problem at all, but here's something I've noticed with my car. When I start it up, it revs a bit high for 10-30 seconds, and then it drops to it's regular idle. If I don't wait for it to drop, and just start driving, whenever I get it on it there's some definite hesitation. If I wait for it to drop back down to normal idle before taking off, I never get this problem. Make sure that it's not something silly like that.
Hope you get it fixed whatever it is.
i got the same problem... (including the 1300 rpms on startup, when it should be 800 or 900)
only when its cold... when i let it warm up its perfectly fine...
at first it used to do it 10 times worse and the MIL would flash... so i hooked up the SnapOn Motis to it and looked at the freeze frame and determined my Cam Shaft Position Sensor was bad... ... i also had mutiple cyl misfires...
i replaced the sensor and i still get the "cold engine" hesitation, but thats it... runs fine otherwise and no more MIL at all...
i'm still trying to figure this out... my motor was still all stock (bolt on wise) when i first noticed it...
I also noticed that when its cold and its hesitating... its feels like its losing a cyl... because it struggles with 2nd gear at 10 mph and 5th at 55 MPH... the Vaccum gauge drops from 18 Hg to around 10 ish (at idle) and literally sounds like my second gen when a coil pack goes bad... ---- i replaced the coils... same thing... my plugs and boots are only 6 months old... maybe... maybe 5 ... AC Delco Platnum correctly gapped, and XACT Heavy Duty Boots...
i'm still very o.O
the only other thing i can think of at this point is maybe its a fuel cutoff or reduction maybe, because spark is good... but i still lose a intermitately lose a cyl when the motor is cold...
EDIT: one more thing to note ... my motor had a little above 20,000 miles on it when i first noticed the problem...
Edited 1 time(s). Last edited Friday, October 05, 2007 11:09 AM
Ron Carvalho wrote:I have no idea if this is related to your problem at all, but here's something I've noticed with my car. When I start it up, it revs a bit high for 10-30 seconds, and then it drops to it's regular idle. If I don't wait for it to drop, and just start driving, whenever I get it on it there's some definite hesitation. If I wait for it to drop back down to normal idle before taking off, I never get this problem.
Same here, experienced it bogging down when I just decided to take off like 10 seconds after startup.
2001 Olds Alero (LD9)
650 whp / 543 ft-lb
@turboalero
Any idea what causes this on our cars? I mean, it's not too big of a deal to wait a few seconds before taking off, but it'd be nice to not have time to buckle up, adjust the seat, review mirror, pop in a cd, change the bass, unlock my passenger door, roll down the windows/sunroof.. etc. You get the idea.
i get this sometimes to... it looks like its not limited to one motor.
My car idles at like 800-900 rpm every startup, unless its really cold, then its more like 1000.... then it calms down a bit when its warm.
I dont get a sparatic idle ever, and the car will hesitate more before its warmed up, but still does it when its warm.
Since I have replaced darn near everything under the hood (upgrades, or just OEM replaced) -- the only thing i can think that might cause it, is Knock and Ignition Retard.
Thoughts?
interesting ... 2200, 2.4 LD9, and Eco ... all have the same problem
more interesting... my 2.2 in my 93 is the exact opposite... its great cold... and gets slower and slower as it warms up...
and in the summer time i get a real bad lag in first gear
My car used to be kinda laggy, a little, but with the mods on it now youd never know that happened. (its still not real fast or anything, but its got enough power to actually feel like its accellerating the whole time youre on the gas)
I wonder if anyone in the "tuning" world knows if theres anything in our computers that causes this, because Ive read that a bunch of people experience something like this.
My car only idles high in the cold, otherwise its a beast, on a cold day driving for the first few minutes it feels faster than when its warmed up... I dont drive real hard untill it is, I just did it a few times when i noticed it at first.
But the warm idle is a lot nicer than the cold.
i'd really like to know the answer/solution to this... granted i dont need to haul ass off at start ... but knowing the car will do that doesnt sit well with me... i mean basically its like.... i know my car is "@!#$ up" if i try to do this... ya know
It does it all the time..not just when cold..it has a definate miss at idle as well...if you slam the gas ton it is fine and shifts down into the passing gear but if you ease it on itll stumble and then go...
^mind you my comment was in reference to that happening only at startup, just like everyone else. not sure why it happens
2001 Olds Alero (LD9)
650 whp / 543 ft-lb
@turboalero
You could try your TPS (throttle position sensor). I had this go out and it would stumble at cruise speeds below 3k rpm. Also, it took a very long time for a the computer to throw a code before I figured it out.
I have noticed on my car that cruzing down the freeway it feels like it is trying to shift between gears and the tach will jump about 100 rpm its kinda weird! any idea?
Teknik: if your automatic... it could be the torque converter lock up solenoid.... when it locks the converter the RPMs jump down Kinda feels like a partial gear shift
Yeah it is a auto. So is it "normal" or is somthing going bad?
Matt Linke wrote:on a cold day driving for the first few minutes it feels faster than when its warmed up... I dont drive real hard untill it is, I just did it a few times when i noticed it at first.
Same here, it's real tempting to get on it, even though I know it's bad to rev high until it's nice and warm.
Also, with the TPS sensor suggestion. Mine has done this with 3 different (not nessecarily new) sensors, including one off a 2.3 HO motor (stole the TB).
Id like to think its an easy fix like that, but this many of us have TPS problems? doesn't seem likely to me...
heavyclutch wrote:You could try your TPS (throttle position sensor). I had this go out and it would stumble at cruise speeds below 3k rpm. Also, it took a very long time for a the computer to throw a code before I figured it out.
This also happened with me, especially with light throttle on a slight uphill. Replaced the TPS and fixed that problem, but the car has always lugged a little in 2nd gear depending on how I am with the throttle. If I shift into 2nd and just keep my foot at about half throttle it will lug a little until after 3k, but it does better if I shift and gradually keep giving more throttle. It has been like this with both TPS sensors so I don't know if that's it. I'd like to see what kind of KR numbers I'm getting because it almost seems like its pulling timing until after 3,000-3500 rpm.
i noticed today....
i started up the car and was late as hell to school
got on it right away and i felt like at 5.5 grand in first, the pressure pushing me to the seat was gone and i started coming forward...
i shifted in to second and moved to the next street... i gave it maybe 2/3rd throttle and it started hesitating at about 3 grand and the CEL/MIL light started blinking... (Multiple cyl misfire detected) ... then it just normalled out... -- and the temp was half way on the guage
(once i get to operating temp... my car acts perfect)
before it normalled out... when i let off the gas, foot off the clutch, still in gear ...
Vaccum: 13 Hg
Normally when i do that
Vaccum: 20 Hg
so after class (its literally a 4 hour class) i started it up... cold
It idled at 1300 RPM
Vaccum: 15 Hg
i let it sit for 1 minute and idle
idle 1000 RPM
Vaccum: 18 Hg
and when it warmed up
idle: 800 RPM
Vaccum: 18 Hg
so when it hesitates... im losing vaccum and misfiring...
when its warm, it runs with no problems.....
any ideas?
Where is the TPS located on a 01 Z24?
Do you have any codes. My car had a hesitation just above idle at part throttle. Turned out to be the o2 sensor, but I eventualy got a code for it.
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