High fuel consumption , Low rpms idling (600-900 rpm)

[akawants]

Hi guys.

 

I am writing here as the local garage could help identify the problem I am facing so I would really appreciate some advices how to fix it.

About the car, recently I have noticed car consumption really high as low as 20-21 mpg. So I decided it was the time to change spark plugs as car was feeling really lazy. After the spark plugs the mechanic confirmed it was pretty bad, really foggy. After few days of tests I could feel the difference in pull but consumption still high as 25mpg in normal driving conditions.

Today I have decided to go to garage to investigate, maybe ECU can tell me what's happening. Diagnose came clean and mechanic decided to open oil cap and smell the cap and he said is really strong the smell of petrol and shouldn't be that and I do believe he is right. My process of thinking is high petrol consumption and strong smell of petrol inside the engine something is off. After all 'the magic' happens inside the cylinder.

I went home and took the Battery off for one hour and put the Battery back. After 10 minutes I checked if ECU has reset. But I noticed now first cold start is idling around 600rpm and after warm up around 900. Because of low rpms car now vibrates. It is weird as I was driving even gearbox engaged , low as 800 rpm.

 

I would really appreciate opinion can help finding the possible issue.

Thank you

[IS300FSPORT]

Way too many variables...

I recently resolved a similar issue on a friends car not a Hybrid.

- Dirty throttle body - cleaned

- MAF Sensor - Cleaned

- Air filter replaced

No codes started behaving...

Try topping up with quality fuel Shell V Power & give it a good motorway run aka (Italian tuneup) carbon build up, doesn't help if used mainly on short journeys.  Idling at 900rpm is pretty normal in cold weather your using more electronics engine compensates but will quickly switch to EV. Assuming you have posted in the right section this is for the IS300H. 

[akawants]

I forgot to mention the car. My daily drive is a Lexus IS250. It is odd as cold start this morning was pretty normal sitting around 1100 rpm and after warm up around 900. I will put some premium soon as I finish what I have in the tank.

I will keep an eye in next few days and see how behaves. If issue probably I need to check air intake and maybe clean throttle body. No faults yet gives me 'carbon issue' vibes.

I am coming back with updates as soon as I find out.

[IS300FSPORT]

28 minutes ago, akawants said:

I forgot to mention the car. My daily drive is a Lexus IS250. It is odd as cold start this morning was pretty normal sitting around 1100 rpm and after warm up around 900. I will put some premium soon as I finish what I have in the tank.

I will keep an eye in next few days and see how behaves. If issue probably I need to check air intake and maybe clean throttle body. No faults yet gives me 'carbon issue' vibes.

I am coming back with updates as soon as I find out.

Nobody can give you a real answer online without seeing the car & doing diagnostic, unless its known as a common issue. Perhaps if you post or move to the correct section you may get a better reply from owners with the same car 

[Robertdt]

Hes posted it in the IS300H, IS 250 and IS200T forum and he has an IS250,   just sayin

Rob

[IS300FSPORT]

Cheers Rob - cant say have seen any posts on here for the IS250 must be very rare not to say there aren't any. Its usually IS300H (primarily) or the IS200T owners posting on here.

IS250 is popular for the previous gen thats why I suggested try posting in that section somebody who has experienced the same issue may be able to help. Will let original poster confirm.

[ColinBarber]

On 11/29/2023 at 7:46 PM, akawants said:

My process of thinking is high petrol consumption and strong smell of petrol inside the engine something is off. After all 'the magic' happens inside the cylinder.

Too much fuel. I’d get the fuel pressure and injectors checked.