jonny2k

This is a little story that I wanted to share with all of you to thank the wonderful family and forum of Club Lexus and LexLS.com, because I would've been lost without these invaluable sources! Hopefully if any of you out there have problems with a sudden loss of power, this thread will help point out some suggestions to make your diagnosis go faster. Anyway, here's my story:

So my father called me a couple weeks back as he was driving his 1992 LS400 and said it was barely accelerating, almost like he was towing a semi truck. He'd had a sudden power loss out of the blue and the car would barely move even if he floored it. I had him stop by my condo and told him to leave it with me and I'd try to figure out what was the culprit.

I've worked on mainly VW's and Honda's but I'd yet to work on my own '98 GS300 not to mention my dad's car. Thank God for Club Lexus!! I researched CL under many different topics and it seemed the culprit was likely one of three things: clogged catalytic converters, a bad ignition coil, or a bad/disintegrated distributor cap and/or rotor.

I first checked under the car while it sat roughly idling and looked under at the cat converters to see if they were glowing red. They were not so I eliminated that as the problem. The next thing to check was the coils and the cap rotor but being the first time I'd looked at the LS engine I didn't know where to start. The first thing I did was check this invaluable and unbelievable site:
http://www.lexls.com/tutorials/ignition/sparkplugs.html

After disassembling the engine covers and exposing the plug wires, I fired up the motor and started pulling the plug wires off the cap one at a time beginning with the passenger side. In this case each time I pulled a wire off, the motor hiccuped and you could see the spark arcing from the wire....so obviously things were working just fine on that side. However as I pulled off each wire from the driver side absolutely nothing happened....the motor never hesitated at all. As it turned out, the car was only operating on the 4 cylinders from the passenger side....no wonder it was running so dang sluggish!!! So I narrowed it down to either the ignition coil or the distributor cap/rotor on the driver's side.

I removed the bolts holding the lower distributor cover although I didn't remove it....I just moved it around so I could unbolt and remove the distributor cap and inspect the rotor. They were both fine. Finally I removed the ignition coil sitting on top of the motor (passenger side) and connected it to the driver side to see if the motor would fire up. It did!! So there was the problem...Bad Ignition Coil!

I decided that since the car has 300k miles I might as well replace both coils, just in case the other one went bad soon. I also decided to do a full tune up since everything was exposed and open. I ordered all the parts from Sewell Lexus (one of our proud CL Sponsors!!) and they gave me phenomenal pricing and service....about 1/2 the price from my local Lexus dealer Again, I referred the link above at LexLS.com to do the tune up and I'm happy to say the car fired up on the first try!

It ran rich and rough for the first 15 minutes and the Check Engine Light came on and off for a bit, but I figured a lot of fuel was dumped into the driver side of the engine and had to burn off and was causing the O2 sensors to compensate and act a little weird. Eventually the CEL went off and the idle smoothed to a purr and the car is running like a top!

So again, I hope this story helps some of you out if your LS ends up in a scenario similar to this.

Bali26

Thanks for taking the time.

LiCelsior

iTrader: (32)

woot, a successful search user!! good job man.

jonny2k

Yes, I am proof that using the Search function (& trying more than one search!) can actually be successful!!

PureDrifter

iTrader: (10)

i vote for a sticky, titled "SEARCHING WORKS!"

dizzyd

Thanks, I'm using search and found this, mechanics gave me 2 possible problems. fuel delivery and spark plroblem, atleast CL has the coil noted many different posts, so attempting to replace coils first.

dizzyd

Replaced coils, wow, she works again. But how dumb is that driverside coil placement (and it's the one that failed). By the looks of it from previous owner, they only changed the passengerside/middle one. left the other untouched. Now going to do a tune up, since caps looked trashed.