Ls400 Judder

[carlo]

:duh: Hi Guys,

Please help throw some light onto this problem. I posted a few weeks ago about the judder at mi-speed. Things getting progressively worse.

1990 LS400 142,000miles. Recently started to judder at 40mph after running for 15 minutes or so & having accelerated OK. Had plugs changed. Air filter. Petrol additives to clean jets etc. No change. Sent to garage. Diagnostics showed code 41 so new throttle position censor fitted. Worse!

The diagnostic also showed Codes 25 & 26 ( air fuel ratio lean / rich respectively ) but garage said that was related to need for replacement cat at OUCH! cost. I don't want to be paying big bucks for new cat if that isn't going to solve the judder problem. But will, if it's the problem.

The judder was so bad today at 40mph car almost stalled. Revs are OK at idle. This problem doesn't happen till car has run for awhile so garage wasn't able to feel it.

Advice please before going back to garage & becoming much poorer!!

Thanks in advance.

JM

[simontaylor]

I suppose the garage have given the throttle body a very good clean.

If you think the injectors may be blocked at all, it is jut a tenner each to have them serviced. see here....http://www.injectorcleaning.co.uk/index.htm

[ontheroad1]

cats can be removed on this year model ( legally ) so that's a saving and wont effect the MOT so I recon fitting spark arrestor on the last 2 O2 sensors should eliminate this problem with cats removed,

o2 sensor just screws in the top which takes the second sensor out of reach of the first one so they cant match readings which is what sends the fault code saying its your cat.

https://webspace.utexas.edu/krk342/Pictures/Nonfouler2.JPG

[carlo]

Hi Guys,

RE: judder problem. Seems sorted with a replacement throttle censor. Will be taking on a long run to confirm soon. Thanks for the tips & comments.

Cheers,

JM