dmonty

My 92 sc400 will run perfect until it gets warm than goes on 7 cylinders, I let off the brake pedal and it shakes like crazy, hop hop hop. Don’t know what to do..

Just changes plugs, wires, caps n rotors and still there. When it starts this problem the valves are ticking left side quite loudly.

After I shut it off I’ve got loud pings from exhaust? I think. I know o2 sensor is bad right bank but don’t see how this will affect the engine missing

Last week I got 3 full days of running perfect and now it’s back, from what I’ve read here so far, really the only thing I think I can do myself is to possibly change the coils and or suck it up and go to the lexus dealer and have them look at it.

Also, trac and check engine light is on, previous owner said it’s been on for a while, goes off at times and comes back; also coolant light comes of periodically. I asked the pervious owner what work he’d done to the car and he said not really anything out of the norm, said it never really broke. Hmm

I’m thinking possibly the plugs I put in are being rejected by the engine après getting hot ? Possibly reverting to factory plugs ? I’m so stumped

Help!

-dean

will1991

I have a 92 SC400 and these are my exact symptoms. Have you found the problem yet?

bugjug

See if you can track it down to a particular cylinder, and then swap injectors to see if the problem moves?

Trac and MIL on due to bad o2 sensor is common, I'd replace that first..

auk113

replaced my O2 still didn't have this issue... i'm in same boat... will be looking for solution.

FatBrian81

iTrader: (2)

Excessive ticking and clanking in the cat usually means there is unburned fuel getting in there, that would also explain the bad o2 sensor. You said you could hear ticking on the left side, try pulling the plugs on the left side and see if there is one that is noticeably different than the other three, that may be your dead cylinder.

SC_coupe

About the valve noise, All 1UZFE V8's will make that tapping eventually.

http://planetsoarer.com/camshafts/camshaft4.html

If you're hearing this, its normal. If you're hearing a different tapping noise than the one described, than it may be something else associated with your rough running issue.