93 LS400, unfortunately sat idle for six years, out doors. Prior to that it ran ok, with only major issue being a electrical leak that would drain the battery in 1-2 weeks when not started.

Started her up the other day after draining old fuel and adding 5 gals of new fuel along with fuel system cleaner. Car runs better at startup and then begins to low / rough idle after warm up. Tach shows rpm’s at 600ish at idle when .

Wondering where to start with this. Seems like it could be a MAF issue, or maybe the engine computer…haven’t done the caps swap yet. Also planning to check the spark wires and pull some plugs for a visual inspection.

Would appreciate if you have any other thoughts on items / systems to dig into.

Thanks - Dave

 

If possible drive the car for 1-2 tanks of fuel then see how it runs. How many miles?

 

Yes, if there was no fuel stabilizer in the tank and the engine run for +5 minutes; bad fuel. Before you added the 5 gallons of fresh fuel, did you happen to notice how the fuel in the tank smelled? If it smelled like turpentine the fuel turned sour.

 

I don't have anything constructive to contribute here it's out of my knowledge wheelhouse - best of luck OP

But I'm amazed that the car sat for SIX years, outside, with fuel in it... and it is able to run, like, at all.

 

I'd focus more on the fuel system to start with. Ethanol in fuel will gum up everything. Pull the fuel pump and see if the sock is covered in gel. Then replace the fuel filter. The injectors aren't as much of a concern but there's always the possibility of them getting clogged too. Fuel system cleaner won't help if the damage is already done, unfortunately.

 

agree to drive it and get all the cob webs out (literal and figurative). a simple tune up might do wonders (plugs, and check the wires and caps/rotors) as well.

also make sure there are no critters that made a home inside the car or engine bay. they love to nest in there and cause issues!

 

Oh I did think of one thing. The tires are probably shot too. They'll probably be good enough for a test drive, but even if they hold air and haven't dry rotted or unrecoverably flat-spotted, they will have aged out to the point where they are dangerous to continue using. Would recommend considering tires as well because they will not grip as well as the tread remaining would suggest they do.

The older a tire gets, the less predictable the grip it provides become and the more dangerous it becomes to operate. Typically the cutoff is 6-7 years from date of manufacture stamped on the tire is the last time it should be used before being replaced, regardless of remaining tread.

 

With mine, because it sat for a while, plus everything was original, I changed the plugs, wires, caps and rotors, and ECT sensor. Plus, cuz I had to get to the front water crossover pipe, I did the T-belt/WP and t-stat. But if you don't need a T-belt I wouldn't worry about that.
You should get the ECU done even if you don't think you need it done. If it's not a problem now, it will be in the future.

Critters are a main thing to think of if it's been sitting that long. The 93 I just got had a mouse house that you wouldn't believe. I wouldn't have if I wasn't the one to take it out. It sat in a garage, a nasty dirty garage, for a while before I bought it. The mouse house filled the valley under the intake where the starter sits. Oh, did I say it was filled? I meant packed!!! (it's about 3-4 inches deep in there) Leaves, insulation, wood chips, and those little helicopter thingy jingies. I got as much out as I could using scrapers and spoons and a small vacuum. (it's very tight to get in there) I wasn't taking off the intake, unless I really have to. I'm just hoping my rough idle and low power isn't knock sensor related cuz of the mice. I have no codes.

Edit; Was this your car before it was parked? It's funny 400fanboy mentioned the old tires cuz, (also with the one I just got) the guy told me "it has brand new tires". The little dibbits (whatever they're called) were still sticking out the side. Brand new....HA. I didn't look at the date til after I drove it home over 300 miles at 80 MPH steady. The dates were 2013.......8 year old brand new tires.

 

flush the cooling system out too. coolant is only good every 2yrs 24k on these if using the correct Toyota Red

 

Just posted a question and realized I never closed this out...

Simple fix....new set of plugs. After sitting for years, they must have gotten gummed up, or maybe the old fuel contributed. Either way, a new set up plugs had it running pretty smoothly again.