91 Ls 400 Went Down,

[md91ls]

I left home for groc., got about 200 ft. almost died on me . went back home in reverse,shut it off.restarted fine with rough running and shaking, acts like its flooding, strong smell of fuel. cil on. pulled codes #21 #28 #71. any feedback would be appreciated. were should i start ?. thanks in advance,desperate. need car for work. thanks

[landar]

I left home for groc., got about 200 ft. almost died on me . went back home in reverse,shut it off.restarted fine with rough running and shaking, acts like its flooding, strong smell of fuel. cil on. pulled codes #21 #28 #71. any feedback would be appreciated. were should i start ?. thanks in advance,desperate. need car for work. thanks

This site shows codes and meanings. http://www.lexls.com/tutorials/intro/codereading.html

Do not know for sure but it might be a coil. Did you check for spark on each bank of cylinders?

[billydpowell]

if you dont talk to us, we dont know what you are doing?????????

[md91ls]

if you dont talk to us, we dont know what you are doing?????????

[md91ls]

I unplugged each coil one at a time, will not start at all . any other ideas or advice? must not be a coil, right. it still starts fine but seems to be missing or flooding, no power. help. thanks in advance. MD91LS

[curiousB]

It should be able to run with one coil. It won't sound pretty but it should be able to keep running.

Are you saying it won't run with just one coil disconnected? Did you reconnect that one and then disconnect the other? Or did you just disconnect both?

i.e.

Coil A Coil B

Test 1 both coils in car runs.

Test 2 unplug Coil A see if car still runs.

Test 3 plug Coil A back in and unplug Coil B. See if car runs.

If Test 1 & 2 works but not test 3 then replace coil A

If Test 1 & 3 works but not test 2 then replace coil B

[billydpowell]

did it set any codes? be sure to run curious' test and reply

[md91ls]

it will only start with both coil plugged in . take coil a loose it dies,plug it back in it

starts, dont sound to good . dissconect coil b it dies. reconnect, starts and runs the same. willnot start with coil a or b disconnected.runs terrible with both connected. any ideas? please reply. thanks

[fsuguy]

As mentioned earlier, with a single coil functioning well and no other electrical problems, four cylinders (in both banks), will fire and the engine will run, but sound really rough; also, more likely than not, your catalytic converter will glow cherry red from the unburned fuel igniting in there! If this is the case, Oxygen sensor CEL/MIL codes show up as well. In your case, you have #21 and #28 (main right & Left sensor issues). If both coils are on the way out, and it sounds very much like they are, then replacing them is called for. If you sign up with Sewell Lexus as a LOC member, you get slight discount on parts and a coil would run about $72+shipping. If you do identify that the coils are the culprits, the driver side one is a pain, but there are tutorials on here somewhere; the other one, just in front of the right bank of cylinders is a breeze and can be swapped out in about 30 minutes to 1 hour for a neophyte with the right tools.

On the other hand, and I am not too sure about this, so someone more proficient with the LS400 fuel system could chime in here (There are several very knowledgeable folk in here with years of experience!), since you mention a strong smell of fuel, something else could be the culprit - perhaps a faulty fuel pressure regulator, pulsation damper, or something in the fuel circuit. Sometimes even something as simple as a broken vacuum hose can affec the fuel system.

Was something done to the vehicle recently that may account for these symptoms?

By the way, for all the engineers in this forum, given the similarities of the problems we are running into, and the almost eerie predictability with which certain parts break/malfunction, what is the probability that these occurrences are purely random and not engineered?

Good luck and let us know how you resolve this :)