msweber97

on my 93 ls400 i have issues with it missing out sometimes it runs just fine other times rough as crap. Engine light does not stay on and the code i pulled is rpm signal no.2 Is this the cause of it? What should i do to fix this? Tune up was done about 10,000 mi ago need to check distributor caps but wanting to see what the cause of this engine code could be.

LScowboyLS

could be an intermittent coil or igniter, also cam position sensor, or failing ECU caps are the most likely 4 things - if you had a code 13 and it ran bad all of the time or not at all, then it is usually timing belt off a tooth.

msweber97

the car was my sisters fathers car and it didnt get drove very much at all the way it misses out bad at times im surprised its not throwing a misfire code. when its idling you can hear it missing out from the exhaust but like i said sometimes it runs perfectly fine and sometimes like pure crap then it clears up a bit.

msweber97

well finally had some time to mess with the car, seems to get bad after getting in the gas a little bit or hard, i had the service record pulled from lexus and when they did a tune up they only replace one plug wire and all the plugs. After seeing that i replaced all the wires, both caps and rotors. The passenger side cam sensor wire was rubbed in 2 i fixed the wiring and ohmed out both sensors and they ohmed good. Pulled the ecu and looked for a bulging or leaking capacitor and nothing looked bad at all. About to say screw it and take it to the dealer to diagnose but wondering if there are any other options to try first. I also unplugged one of the coils and tried to start the car and then tried the other one, car will fire but not run just off on coil hooked up.

RA40

iTrader: (6)

The caps don't necessarily have to be leaking to be bad. This is Yamae's test for the ECU:
https://www.clublexus.com/forums/ls4...-by-yamae.html

Any other symptoms with the car, like poor MPG, hesitation? Do you know which cylinder/s are misfiring?

msweber97

i seen that test and need to get a good meter to do that, not sure which ones are misfiring. The thing will feel like its running half power sometimes keep jerking and clear up and then take off and other times it may run perfectly fine if you stay out of the pedal. ac and everything works in the car, its just this damn missing out i cant figure out, you can def hear it out the exhaust out the back of the car.

RA40

iTrader: (6)

Alternate thought is injector/s, those usually throw codes though. Pick up an inexpensive meter, $12-$15 will get the basics done for car related stuff.

msweber97

i have a meter i got the other day, when i get a chance im going to get the codes pulled again and see if anything new has come up that i have not caused, with how bad it runs sometimes im surprised the light isnt on all the time. going to pull the covers off and listen to each injector to see if one isnt clicking like it should be also.

msweber97

well pulled the codes and apparently i have no codes both the engine light and od off light flash rapidly. so either computer hasnt picked any codes up or not able to store them...?

msweber97

finally narrowed it down i believe, had my friend rebuild the ecu today reinstalled and still had a miss no better really. I unplugged the air flow meter and drove it and had zero miss to it and no hesitation so im guessing its bad. The question is will i cause any damage by driving it with the afm unplugged until i get another one?

msweber97

swapped out afm and no luck, hard to believe that leaving it unplugged there is no issue but plugging it back in i have all the issues......

RA40

iTrader: (6)

The caps were spec'd from the ECU thread when fixed? Any CEL would store a code so the absence of that leads me to suspect the ECU still may have issues. Does the A/C work? Any shifting issues?

msweber97

yes the caps are the ones specked on here, the ac works shifting is perfectly fine just a damn miss that i cant get to come back on to pull a code again. when running the ac it does seem like the motor is a little louder then usual like a whining noise if that makes sense.

msweber97

So, has anyone ran their car without the afm plugged in and been alright? So sick of the missing out I'm about to leave it unplugged.....

python

iTrader: (4)

ohm ur coils out
do a cylinder balance test as well if ur coils test good