nevermore

Hey guys, i recently bought a 1996 ls400, it has 200,000 miles. When i first bought it, it had 4 codes for random misfire, and then misfire on cylinder 3, 4 and 6. It would also push out white smoke that smelled like gas almost from the exhaust. The misfires only seemed to happen when the car ran for a little bit and started to get warm. I replaced the spark plugs and ignition coil wires. that didn’t do much so i decided to take a look at the ECU and of course I had leaking capacitors, so i shipped it out and got it repaired, after i got it back there was no more smoke and it shifted smoother. It still misfired but only threw one code which was cylinder 5 misfire. I’d appreciate if someone could enlighten me on why and what i should try next. (side notes:speedometer isn’t working reliably, probably going to replace ignition coils and distributors but not sure if i should) THANK YOU!

Superfast1

I recently had a misfire on 1 of my cylinders & traced down to a bad spark plug wire even though I had replaced the wires with Denso only 5 years ago. Here's what you should do as part of the troubleshooting: Remove the cover then swap spark plug wire 5 with either 3 or 7 which is right next to it then start the car & let it runs for a few minutes. If the error code changes from P0305 to P0303 or P0307 then you've found the problem. If it's the wire & since you've just bought the car, I suggest you should go ahead & change all of the wires. Good luck.

dwoods801

If they are OEM spark plug wires then they should have a date code on em, but give them and your plugs a good inspection and replace all of them if they are clearly getting up there in age. Make sure to get OEM Denso components for these parts. Also check for oil in the spark plug tubes and at the bottom of the valve cover for leaks, check your pcv valve, and replace anything that is brittle or damaged. Does your car have the EGR system? I would consider deleting it if it’s equipped and you won’t have any problems when getting emissions done in the future.

timmy0tool

iTrader: (7)

after plugs and wires, i would look into the distributor caps and rotors which should have been replaced at least once at that mileage.

nevermore

hey guys, spark plugs have been replaced already and so have the ignition wires, they look clean and there are no signs of oil, yesterday when i went to start the car up it ran super smooth, like brand new.
This morning I started it hoping my issues were resolved but i started it and it idle really rough and i wasn’t able to rev over 2k, on top of that there was a strong gas smell from the exhaust, because of how bipolar the car is with running i believe it to be a electrical issue more than a mechanical issue, I’m going to look at the ECU even though it was just repaired, any other suggestions?

Gerf

I'm not saying this is your problem but it was a documented issue in the 90's on some Toyota models mostly Camry. The fuel pressure regulator would fail resulting in hard starting, running rough with quite a bit of smoke until the rich condition cleared up. Some would run rough until they were repaired, the cause was the diaphragm I believe.

Lots of people had valve seals done at garages before taking the car to the dealer, anyway something to think about if your symptoms are similar.