My 1998 5 speed Z-24 has recently developed a hesitation I was wondering if you guys would have any ideas on.

Its a sporadic problem when I accelerate off idle the car bogs and there is no throttle response for a second. It only seems to be off idle and if I rev above 2000 RPM there is not as much of a bog. It is really getting dangerous on hills or leaving a light with a tailgater.

In addition the car will idle smoothly for a minute of two and then sort of stumble and the revs drop. This occurs for about five seconds and then the idle returns to normal.

I recently replaced the fuel filter and that didn't solve the problem. The spark plugs were changed last year and no warning lights on the dash have lit up.

Any help you guys could provide would be greatly appreciated as the problem has become more frequent as of late.

Thanks again.

I had the same problem on my 98. Never did find out what the issue was.





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I'm having the exact same problem..right down to every word. I so far replaced the tps, iac and complete throttle body..I had good spare parts sitting around so i fitted them. I've also done the plugs as well. My car flaged a fault for the upstream o2, but the light didn't stay on...I'm thinking it was historic. I noticed if i pump the brakes only 5 times rpm rises (normal) but up to about 1,500. Once I release the pedal about the 5th pump the car almost dies by tumbling down to 300-400rpm.
Right now I'm leaning towards a faulty map sensor, but I don't have a spare nor am i gonna buy a new one for $100 and find out it didn't do jack all. So saturday I'll head over to the junkers and pick up a map. If the map doesn't work, I'll do a smoke test and check for leaks..what gets me is there doesn't seem to be a fault flagged to cause these problems
..I'll keep you updated when i find anything out

Shifted wrote:I had the same problem on my 98. Never did find out what the issue was.

I have a 98... mine does the same thing

Mine did the same for a long long time and I couldn't figure it out, and it was overheating & loosing power at take off. like it would take a second to respond and then takes off.
Finally they found a blown head-gasket because the overheating was getting worst.
but that's a different story.

it might be the MAP sensor, not 100% sore

sure*

try replaceing spark plugs and boots with OEM stuff only (ac delco) i had the same problem mine seemed to of went away i think. Also blow out all the junkt hat maybe in the plug holes.

Sometimes it hickups at take off.... and it tends to lose coolant over time.... wtf whicht hen makes it overheat... Weird...

it has to lose alot of coolant to overheat if its overtime it loses it i dont think its the coolant making it overheat unless its overtime too..lol

Thank god i'm not the only one w/ this problem! I also have a 98 Z24 w/ the same problem. mine could be worse though. i work about 11 miles from my home. i cant even get home w/ out the car acting up. i hit the gas, it spits and sputters like i'm missing something... no air or gas ... something. i usually just pull over, turn the car off and let it sit for a couple mins, start it up and continue on my way home. i was actually thinking of replacing the fuel pressure regulator. i replaced coil pack, tps, spark plugs, both exhuast o2 sensors, IAT sensor.... i'm lost w/ this thing! i actually have a 97 2.4 motor i'm working on to put in, but i need the car to run till i get done w/ it. if anyone figures this problem out... please let me know!

Jason

I believe I solved the problem ppl, I got fed up today, and wasn't gonna spend $100 at dealer for a map sensor to find out it isn't that..so I went to the junkers, they had only 1 sitting around for $20... "SOLD"!!! After a 2 second install of the map sensor out of a '96 grand am...PRESTO!! car functions like it should, with out any idle/spudder/loss of power problems. It's raining here and for me usually when it rains i don't get to many problems, but it happened today and since i changed the map sensor this morning..it stopped. Although this problem with the idle/spuddering doesn't happen all the time, but it would for sure do it at least once in 2 days..so i'll keep you all updated

i have had the same problem here with a 97 2.4L manual. I hope you found our solution. please let us know in few days to a week if any further problems.

yino18 wrote:i have had the same problem here with a 97 2.4L manual. I hope you found our solution. please let us know in few days to a week if any further problems.

Well I did about 90km's today so far, and no problems *Knocks On Wood*

MY brother had the same problem in his old 80 z28 camaro be4 the computer age in those cars and it ended up being the brake booster it had a fractured in the diaphram so it was losing vacum .I know losing vacum will make the car functions like that so i say look at the brake booster .One of the things no one ever looks at

Well guys, so far I've gone 200km's and no signs of a problem yet..usually it would of happened by now...if you have this problem, do what i did..go to the junkers and pick up a map..it'll cost $20 or so..maybe less.
I'd try it somemore, but I blew out my ankle during a indoor football game last sunday..hehe so the car ain't being driven to much now

the problem is your o2 sensors replace them and your good to go, it happened to my ford focus before i sold it, but i replaced the 02 sensors and it was like driving a new car again

CAV2NV420 wrote:the problem is your o2 sensors replace them and your good to go, it happened to my ford focus before i sold it, but i replaced the 02 sensors and it was like driving a new car again

I had a very mild case of this particular problem. It was so insignificant for me that I never looked into it. But the day I threw a code P0402 (I THINK) for the post-cat O2 sensor failing, I changed that sensor as well as the pre-cat O2 sensor in the exhaust manifold just for the hell of it. That did the trick! Replace both O2 sensors. MAP sensor and brake booster/other vacuum points are good to look into as well.

Thanks guys,

I've been away on business the past week.

I left the car at my parents and my father pulled some of the sensors to see if any were really gummed up. He said one had a lot of carbon and crud on it so he cleaned them up.

The stutter is still there. I'll see if I can get a MAP sensor this week. If thats not the problem I'll look into the O2 sensors as well.

Thanks again for all your input.

Update.

I tried to test the MAP sensor while on the car with a volt meter.

When I looked closer I noticed the vaccuum line had developed a cut where it meets the sensor.

I replaced the line and the car now runs as smooth as it did when it was new.

Nice that the fix was so cheap!!

ok..so it's been awhile, but I'll post my solution to this prob i had incase someone else has a silimar situation
I ended up changing my map sensor for one at the junkers, cost me like 20 bucks ..it worked for about 2 month and the car started up again with it's hesitation
What didn't dawn on me at the time was that when i replaced the map i fixed a leak in my exhaust up in front of the cat..then the 2months after when it started hesitating again is around the same time i hit my exhaust hard.
When i hit it hard i cracked the catalyst..so i replaced the catalyst and VOLLA!!!
I kept getting a O2 sensor fault with the light not coming on, this is before i replaced the cat...but i had changed the O2 sensor and couldn't figure out why it still was flaging a fault
Ne-waz long story short, my hesitation and idle prob was due to a whole in my exhaust up near the O2 sensor..the sensor couldn't get a proper reading due to the leak and would set off the air/fuel ratio

man i wonder if the threads on my o2 sensor are @!#$ cause i keep getting the cel ? i going to jack that thing up soon and see thanks for the info. it kinda runs like @!#$ and maybe its leaking too thanks for the ideas

i just fixed this problem on my 96 2.4 with a coil cover (WHITE) and an ignition module

i had hesitation in my 03 sunfire but then i got my injectors all cleaned and @!#$ and it runs like new.



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Exact same problem here, replacing fuel filter helped a little, but still hesitation. Guess Ill check sensors now, hopefully that fixes it...

so douse any one no for sure how to fix this problem i have the same problem on my car and the machanics dont have a clue what it is


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