My GS400 is misfiring in cylinder 3 P0300, P0303. And idling rough/low. I also have codes P1310 P1320 P1330 P1340. And EDIT: ( P0440) P0441, P0446, P0171. Where do I even start with all this? Is this worth fixing for a pretty non mechanical guy?

 

P0300 and P0303 are both misfiring codes. P1310 is the Ignition Circuit Malfunction. P1320 is ignition related. P1330 is Spark timing adjust I think? P1340 is another code stating an Ignition circuit malfunction. P0440 is an EVAP system malfunction. P0441 is Evaporative Emission Control System, Incorrect Purge Flow. P0446 is EVAP Control System Vent Control Circuit Malfunction, here is a link concerning Code P0171
https://www.clublexus.com/forums/per...1-threads.html

Does this help?
The issues you are having could be caused by; Spark plug, wires, MAF, IACV, TPS, Coils, dirty fuel, yada yada. It could go on. I'd first check for loose vacuum hoses though. GL!

 

I talked to the guy who I had look at it and he said he had checked out the engine, coils, sparks, hoses. He also reset the computer.

I go to autozone and now I have P0130, P0150, P0153, P0133 which seems to indicate 02 sensors. Would this cause my car to idle rough/low or is it a symptom of something else?

 

hows the throttle response when you step on the gas?

i had a similar problem and i had quite a few codes too, it was sensors and something to do with my manifold. I ended up buying a used manifold on ebay with all the sensors for under 200 (dealer wanted 1400!) solved my rough/low idle as well as my throttle response.

 

holy crap thats a lot of codes

good luck

 

i had all those codes on my gs 300. took the car to the shop to find out that i had leaking valve cocer gaskets that leaked oil all around my ignition coils which probably damaged. my plugs were fouled and 2 of my ignition coils were damaged so i got the valve cover gaskets fixed, replaced spark plugs, cleaned all the oile that seeped down the manifold, replaced 2 of the coil packs and my problem was solved. however, i still have a 2 trouble codes left that i still have to deal with and one is for insufficient engine coolant, and bank 2 system too lean which makes me believe i need to replace the o2 sensors.