This only happens under light or no acceleration. It is much more pronounced under load (going up hill, AC on, hot/humid outside). I thought maybe it was my imagination for a while but today i realized I'm definitely not imagining it. I was going down the highway at 74-75mph, 5th gear, foot steady on the gas to keep it at that speed and it started jerking like crazy. Not so much that it spilled my coffee but pretty badly. I could clearly feel it jerking my body. It does not hesitate at all under full power...
Things I know are wrong with my car:
Need new tires
Front suspension is screwy (popping & squeaking noises going over bumps)
Probably very dirty air filter (cold air, hasn't been cleaned in almost a year)
Throwing a code at the after-cat O2 sensor (buddy w/ scanner told me I prolly need to replace my cat)
Any ideas?
Thanks in advance.
It could be your cat, but it should do it under any load once the cat is warm.
FU Tuning
Maybe it does... it just seems like I only really notice it under harsh conditions (hot & humid, AC on, uphill, etc.) The odd part is that I have tried to feel it under hard acceleration but I just don't. It seems like it pulls like a champ under full throttle.
You're saying it could be my cat though... what exactly is causing the hesitation? Some sort of fuel shortage caused by a bad O2 reading?
Tim wrote:You're saying it could be my cat though... what exactly is causing the hesitation? Some sort of fuel shortage caused by a bad O2 reading?
From what I've heard, most "bad cat" cases involve a clogged cat, which stifles the engine through excessive backpressure. This doesn't really match your symptoms though, since often the engine loses top-end power first, since that's when it has the most exhaust to expel.
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I guess it could be that... wonder what clogged my cat...
I know I'm losing coolant EVER so slightly... Not like white smoke in the exhaust or anything but I have to top it off maybe once every 3-4 weeks because the light comes on...
I don't have any puddles or anything in the driveway but maybe it is burning just enough to have prematurely killed my cat...
First thing I would do, Get all youre piston cyl's psi tested, That should be the cheapest thing to start with first, That would also narrow it down, Whats gone wrong. If everything checks out ok, in that area, Then I would look at the exhaust system, CAT etc.
Good Luck.
My car is doing the same thing, i just put in a 2.4 with HO head swap. After the hesitation start and i come to a stop light.. thet car seems to load up on fuel.. i know this from the puff of black smoke out the back. I adventually stops after a while or after the car has cooled down. My ETS and CES lights come on also. Weird thing is when my car does this jerky thing my ABS and BRAKE light flicker briefly. I just put the motor in and never had this issue before the new motor. Only thing that is different is the Motor and ICM. I do have very old stock exhaust still...
3800 SII S/C Swap <In Progress>
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I just hooked the scan tool to my car this evening and found my bank 1 O2S ( pre cat) was throwing 3 codes. Basically it is not working. I watched the activity on the scan tool and it never went below 300 until it did a jump from 568 to 00 and back up when it did this my car started to studer again. I am replacing this tomorrow.. i will let you know if it help my issue.
3800 SII S/C Swap <In Progress>
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i had a similar issue and i replaced the cat and problem solved. car runs great!
do you guys think the slowly leaking coolant could have killed my cat prematurely? if it is in fact burning and not leaking...
If youre getting coolant down the piston cyl area, That would cause some issues with youre cat, Also O2 sensors as well.
