weird behaviour after oil change..

[BrettZ]

I have a 2005 base vibe auto with about 55000 kms I switched to synthetic 2 days ago, and ever since the oil change the engine dips to 500rpm and almost stalls (but never does) when coming to a sudden stop such as a yellow light.Also when I'm traveling about 45mph and taking a shallow corner the transmission downshifts and upshifts again.Sometimes when taking a right or left from a stop sign the engine will rev to about 4000rpm before shifting to 2nd (at normal throttle)no CEL's or anything, not leaking any fluids whatsoever.Any ideas? I really hope I didnt screw it up with the oil change, but I don't see how I could have???Thanks!!

[tribalman]

Quote, originally posted by BrettZ »ever since the oil change the engine dips to 500rpm and almost stalls (but never does) when coming to a sudden stop such as a yellow light.i've had mine stall out when taking a quick stop. i haven't checked the RPMs when i've been in this scenario, i'm busy making sure someone isn't hitting me or me them. ever since i found this out and i need to make a quick stop i drop the trans into neutral. i have an automatic, not sure about yourself. maybe try shifting to neutral and see if you still have the same issue. doesn't shudder, lurch forward, or stall out.Quote »Also when I'm traveling about 45mph and taking a shallow corner the transmission downshifts and upshifts again. i haven't taken a turn that tight at that speed but i do know that at 30mph and a regular street intersection mine doesn't do that. might be the auto trans trying to be in what it thinks is the correct gear. you start the turn so it shifts down but then there is too much slippage of the wheels so the car thinks its going faster so it shifts up. not quite sure.Quote »Sometimes when taking a right or left from a stop sign the engine will rev to about 4000rpm before shifting to 2nd (at normal throttle) it really would depend on your acceleration the shift points. can't quite be sure.

[BrettZ]

Thanks for the info tribalman.None of these symptoms existed before the oil change. So I'm convinced something must have changed.

[star_deceiver]

Try disconnecting the negative battery cable for 10 minutes or so. That'll reset the computer and let it re-learn everything.Quote, originally posted by BrettZ »The engine dips to 500rpm and almost stalls (but never does) when coming to a sudden stop such as a yellow light.My '09 has done this since it was new. But only when warmed up, and it only does it just as you stop. Pressing and holding the clutch at speed or coasting in neutral won't do it... unless I stop.

[BrettZ]

Will try the ECU reset and post back

[BrettZ]

Well no luck. It seems to want to wander at idle when warm, anywhere from 600-900rpm with tiny surges. Sometimes just even driving down the highway in a straightaway it will downshift and upshift again...I bought the car used from a dealer, it should still have a few weeks of warranty on it. But I'm hoping its not connected to my oil change as that might void the warranty.Going to take it in later this week.

[engineertwin2]

I don't think it is necessarily related to the oil change. Although you say you've never experienced it before, its not uncommon for people to discover symptoms only after maintenance is performed (because they expect to find something wrong).Given, I could be wrong, have you checked the fluid levels? You stated you aren't leaking any, but what is the fill level? The engine stalling in stops and cornering could indicate the automatic transmission fluid is low.It could also be you have a sticky solenoid, causing the transmission to hunt. One thing to note is if the 45 mph speed is around a normal shift point.Changing from dino to synthetic oil alone will not alter engine performance, but using a thinner weight can alter engine load.

[lovemyraffe]

Quote, originally posted by engineertwin2 »Given, I could be wrong, have you checked the fluid levels? You stated you aren't leaking any, but what is the fill level? The engine stalling in stops and cornering could indicate the automatic transmission fluid is low.It could also be you have a sticky solenoid, causing the transmission to hunt. One thing to note is if the 45 mph speed is around a normal shift point.My thoughts exactly. Double check all the fluid levels. If the tranny fluid is low, it will act weird especially in the corners.

[BrettZ]

All fluid levels are normal ATF included.Good news is a 2nd ECU Reset seemed to have fixed the problem. I'm completely baffled. Thanks for your help everyone!*crossing fingers it doesnt return*

[djkeev]

You changed the oil or paid a shop to do it?Sounds to me like something was knocked off and reconnected or even accidentally unplugged during the service.The memory was forgotten and it takes several hundred miles to completely relearn how you drive and how the car should act for you.Repair shops are known to not always have competent technicians and often serious damage can happen as a result of that.Glad it fixed itself for you though.Dave