chrcrou26

Also if any of the sensors in that system fail they all shut down...As I said before it's a closed circuit system

Relex

Thanks, i am sure I can rule out ignition and fuel.... because if i move the tps I can get it to start right away and keep idle without a problem. but then after a while its back to same issue.

when I do get it to start and run right
I look for vacuum leaks and wiggle connectors to try and find the issue but I didn't see or hear anything.

No CEL and once in drive I have no issue..

Any ideas ??? should i still focus on the throttle?

chrcrou26

How's your charging system.....and check your fuses and connections. ...may sound dumb but an alternator going out or a battery going out in any lexus can cause issues our cars are highly reliable but are extremely touchy to fluctuations in voltage or bad or failing grounds.....just today I noticed my 99 gs300 having issues with the ac motor (car bought used) new motor but the grounds and wiring that were done were spliced and left open no tape not butt connector nothing....something I would have never seen if I didn't go looking....soldiered and shrink taped those connections today no more problems it's often the problem you don't think of that's the main issue

Relex

Thank you, I just changed the battery terminals, also changed the battery, I have a spare alternator, same issue... Can it be the idle control motor? or maybe fuel injector.. I tried 3 different TPS sensors and nothing..

also problem occurs when the car sits, that is what makes me think its loosing fuel pressure over time. now I am back to being confused, fuel , throttle , electrical donno what I can at least rule out.

chrcrou26

Sounds like you got one hell of a gremlin lol....umm I agree probably looking toward fuel pressure now....possibly bad spark plugs or injectors....check for oil around spark plug rings...

chrcrou26

Aha....just saw a problem in your first post single prong spark plugs major no no and will reek havoc....oem 4 prong plugs is what you need may fix all issues

chrcrou26

You basically could be flooding the motor....running super rich because your not getting full spark in the combustion chamber....didn't hit me till now but ur slow starts and irratic idleing could all be signs of running rich

Relex

already did that... got the right denso plugs

chrcrou26

Shaking is either not enough air or too much air.....not enough fuel or to much fuel.....you ruled out all the electronics under the hood at this point....

truongrobe

Rpm up and down ?

manosa5

Your fuel pressure regulator is going bad

chrcrou26

Fuel pressure regulator would give him problems all the time....Once the car runs for a minute or two it's fine....fuel pump maybe or possibly cracked fuel rail

Justin2JZ

I'd put a noid light on the injectors.

chrcrou26

Noid light is only gonna show electrical problem which he'd already replaced everything you can under the hood

aliga

iTrader: (147)

My suggestion. Replace the entire tb with sensors.

I have seen similar issues many times and the complete replacement resolves it.

If u need the tb I have a couple.