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Bringing my 147xxx miles/238xxx kms 08'IS 250 to the mechanics tomorrow, but wanted to hear what you guys think might be at fault or similar experiences, had this beauty for more than a year now but over the last few months it developed some issues:
Shifting from 1st to 2nd is occasionally jerky and having a rough feeling shift but doesn't feel like it's slipping.
The car sometimes would be hesitate in acceleration and drops the rev slightly while still pressing the pedal in the same position.
Recently it experienced a unstable revs on a cold start, as it would rev to 1.5k and drop to as low as 0.4-0.5k, but once the engine warms up it becomes smooth again.
Sometimes when stopping at the lights, the revs dips and feels like the cars gonna stall.
Any theories as to the above issues? It's recently serviced in April 23 and transmission has been serviced with fluid replaced(not flushed) in January 23, my main guess is probably carbon build up but there's probably stuff I'm missing. Based in Sydney, Australia.
Last edited by SEchoco; 06-04-23 at 12:37 AM.
Reason: Changing some information
If it does a lot of short trips, I'd suspect carbon build up also. You need to pull the intake and look. Toss some new plugs in it while you're there and clean the MAF sensor. Start there. GL.
Thank you for the heads up, unfortunately I'm not really knowledgeable around cars so I'll leave it with the mechanic to figure that out in the morning, I mostly do longer trips ever since I bought the car (with occasional roadtrips of roughly 3000 kms), but as I have no idea what the previous owner's trips are like, carbon build up might've been an issue before I even gotten the title, it's just now that it's gotten to the point of affecting the way it drives, fingers crossed this isn't too expensive to fix.
So the mechanic says the fault has something to do with the catalytic converter, and he says the plugs and coils should be changed as well. Surprisingly the carbon build up isn't that bad but I still wanted it done. Will hear more from him tomorrow.
So the mechanic says the fault has something to do with the catalytic converter, and he says the plugs and coils should be changed as well. Surprisingly the carbon build up isn't that bad but I still wanted it done. Will hear more from him tomorrow.
Did he list oflisten codes from the ECU? I wouldn't think you need new coils so soon, and failed cats are rare. If it has been running real rough for weeks, it could damage cats. I would want more facts before saying yes to this.
OP - I highly recommend OEM coils and plugs. Denso is good stuff and everything else is 2nd place.
I forgot the codes but it's definitely for the catalytic converter, mechanic said the car was running rich so they're putting together some options tomorrow in regards to that (replacing cats, o2 sensors and what not), he did mention the plugs seems to be wet with fuel too so fuel injectors might have to be looked at too.
I forgot the codes but it's definitely for the catalytic converter, mechanic said the car was running rich so they're putting together some options tomorrow in regards to that (replacing cats, o2 sensors and what not), he did mention the plugs seems to be wet with fuel too so fuel injectors might have to be looked at too.
That list keeps getting longer. Based on what they are saying, that's simply too many failures at once for these cars. Do you absolutely trust this place as I'd be getting a second opinion pronto!
Could faulty injectors foul plugs and kill cats, yes. Is it likely to take out coil packs, no. Could a faulty plug or coil damage a cat, yes. But it would need the check engine light on for weeks with a misfire code.
It just seems fishy to me like they are scamming for high dollar items.
The CEL was on for almost a year (I know, I'm a moron for not having it addressed), but that was when they added some fuel additive to clean the cats, and I always though if it didn't affect how the car drives I'll just leave it, and when I had the cats checked they were fine and weren't blocked, but now it's biting me in the butt, should've gotten it looked at sooner.
Had a talk with the mechanic today and he said both manifold cats were quite bad along with some o2 sensors, and was very certain of that after testing, the car did have a rotten egg smell whenever I accelerate quickly after driving normally, and apparently it's a sign that the cats were on its way out, so most likely it's already going down hill before I even picked up the keys. He did say he'll see if the replacement cats would fix the issues, if so, he'll leave the coils and plugs.
I do trust this shop as they've had a solid track record in the past, and I couldn't really get a second opinion as I need the car back asap for family reasons.
2013FSport Thanks for your feedback on this, and fingers crossed that this will be the last giant repair bill!
Last edited by SEchoco; 06-07-23 at 07:51 AM.
Reason: Added info for mechanic's side
NP,
FWIW many many cars make a mild rotten egg Sulphur smell and pass emissions. If I were you, new Denso plugs, upstream O2 sensors, clean the MAF, a new air filter and see what it does.
For less than $40 you can monitor the some basic parameters. The key ingredent is acting so things don't get worse.
Fix all misfire issues. If those are resolved and it passes emissions (no cell code while driving for weeks or months) then you are good.
06-04-23, 12:34 AM
Possible transmission/engine fault?
