snidehocke

I just picked up a 95 sc400 the other day and it has it's share of issues. There's a hefty leak which is another thread and a REALLY annoying bucking that the car has been doin for the last few days.

the bucking actually began when I was sitting still in Drive w/ my foot on the brake I could feel the engine buck, but the RPMS stay pretty even (like it wouldn't try to die)

then progressively more and more during acceleration it would buck short and quick over and over then it would come out of it and ride ok then buck a few more times at really any speed.


After this problem began, I have:

added fuel treatment / cleaner to empty tank then filled up w/ 93 Octane
Changed the plugs (one was particularly orange/corroded in the plug well)
reset the ecu
replaced PCV valve
replaced three cracked vac hoses (though for sure that was it)
adjusted TPS as mentioned in another topic

Now after all of these things

the problem I THOUGHT was fixed...it wasn't doing at all once I put everything back together and drove to work (long drive.)

well as I slowed down at a toll booth i felt it buck once and I noticed a CEL but it went away when I hit the gas...then again at some point when I was accelerating lightly I felt it twice quickly and noticed an intermittent check engine light a few more times primarily when either braking or decelerating. Now it doesn't buck when I'm sitting still though at least.

I was thinking misfire (and still maybe am) but wouldn't I be smelling some unburnt fuel? Would bad battery/alternator and weak spark maybe do it? Any possibility of torque converter? (hope not!)

Any idears? Thanks

O. L. T.

iTrader: (17)

Engine related, moved.

shern

iTrader: (6)

95 OBD1 Toyotas can have the CEL read with and OBD1 reader.

Zeal3

iTrader: (1)

i had a bucking problem. but not like urs.
but i changed my distributor cap and it rides Smoooooth now.

snidehocke

I think I have coils though right? on a 95 400. I am asking cause I don't know for sure.

ihiryu

iTrader: (7)

do a search on the fuel pump ecu, they tend to go bad, bypassing it only takes soldering on two wires

p3lon

i have the same problem. still haven gone away. i now get a battery light on and a abs light on when i hit the gas..

sc400CTI

I had the same problem changed the main coil (there are two ) and problem when away.

snidehocke

hmm glad to know someone fixed it...how much did the coils run?

RedPhoenix

iTrader: (10)

Had the same problem, wound up my cam shaft sensor wasnt getting a good singal. the wire going to it was severed by the belt



Also, one of my ignition coils died, but it never threw a code... the car just ran on 4 cyl's and it sucked.

SClean4

I used to have this mysterious bucking/jerking. I took it in for maintenance and I think it helped this problem. I still got a little bucking but less extreme.

Now, there's some things I've noticed:

1.) It seemed to buck especially when the engine has been cold or just started up. When the engine was completely warmed up, I think it bucked a lot less.

2.) My bucking seemed to happen always when I would get into what I'm guessing is the 3rd gear (Auto) at 40 MPH.

CyBorG

I have the same issues as many of you. After doing a full maintenance of belts, dist cap, pulleys, cap, and seals, my car has been running smoothly but about 3 weeks ago, my car started also bucking seriously, even at idle(or misfiring, or whatever). Its only at 130k. My mechanic started working at it and began to use cleaners on my fuel injectors and gas tank. That helped about half of the vibrations. Then replaced spark plugs with NGK iridiums and spark plug wires. That helped pretty much 95% of the vibrations. But it is still not perfect the way it used to be a month ago. I am sort of disappointed.

andrewwake

iTrader: (1)

did you replace engine and tranny mounts? could be getting the vibration from those being bad.

CyBorG

No I haven't. The vibration is not constant, it is more of an occasional jerk that causes the whole car to shift a bit (I can feel it from my seat).

sc5spd

you can do what i did and ignored it till i got my 2jzgte lol