GS350 starts and idles during warmup. Severe hesitation to the point of stalled ng when giving it gas. Dies upon reaching operating temp. Obd scans with real time data show all parameters nominal. Replaced plugs,maf,fuel sensor, plenum gasket, throttle body, purge valve, fuel pump. Still having issues. HELP from all of you would be greatly appreciated!

 

All the parts you added were they oem or aftermarket china parts? If oem, then I would leave them! if china parts I would replace them back to oem. The plugs were original lexus or denso and not some knock off plugs?

On the scanner, did you monitor coolant temps, to make sure there normal? Just to be clear, when you first start the car does it run perfect? Then when it heats up it starts to misfire/hesitate? As it does the hesitating have you tried disconnecting the mas sensor while its shaking to see if it clears up?

What engine codes have popped up? When it hesitated did the check engine flash or solid?

 

Sensor iridium's. Tried to use denso for everything I could. Only Amazon part was the purge valve. Not running good when first started. Will stalk when gas is applied. Was initially getting P0171 and P 0174 at the beginning but not now. Yes, watching the coolant temp,fuel trim, O2 volts, fuel gpm,vacuum and a few others.

 

Thank you for asking! I forgot to to thank you in my initial response!

 

What happens if you give it throttle does it get better or worst? Was the car ever sitting for a long time?

Maybe you can rent a fuel pressure gauge, and test the fuel pressure. If fuel pressure is good, then maybe its fuel injector. But I would try to avoid throw parts at it, and instead diagnose stuff. If you are unable to diagnose, take it to a mechanic and just pay for 1 hour of diagnostics. Then repair the issue yourself

 

It has sat for awhile. Bought it from an acquaintance who let it sit for a long time. Ran good for awhile then this issue popped up. Undriveable at this time as it dies when our Into gear. I can rev it to about 2500, after that it bogs. Major hesitation when transition from idle to acceleration. I think it may be the fuel pump I put in. I could have made a mistake when installing it. Inspecting it now

 

It sounds like a fueling issue! I would reinstall the oem fuel pump, as the oem is extremely rare of going bad in our cars. You could have stuck fuel injectors.

 

did you replace your fuel filter as well?

 

Thank you for the info! Yes, I replaced the filter. I think I will put the original back in.

 

Was the MAF replaced with OEM?

 

Original fuel pump back in. Still same issue. Gonna pull injectors in bank 2. Short term trim was high on that side compared to bank 1

 

Denso Maf. Tried to do denso or Lexus wherever I could

 

if it were me, I might bite the bullet and take it in and have it diagnosed. it sounds like a lot of parts, time, and energy so far.

 

Pulled the injectors. Extremely dirty. In the process of cleaning them. Will finish them over the weekend

 

Are you cleaning all 12? If you just clean the top 6, you might as well dig deeper and clean the high pressure injectors.