SeanHRCC

I searched the forum and couldn't find what we are facing so i wanted to see if i could get some advice from you guys. We have a 1998 GS300, and as of last week it was running perfectly (aside from an O2 sensor that needed to be replaced)...one day it started having weird acceleration problems (rough idle, very rich smell coming from exhaust, etc). We did a tune up as i figured it needed one (plugs, wires, oil change)...MAF is fairly new (about a year old)...but we were still having the problems so we took it to a family friend who has a shop.

He called me this morning and said that it needed essentially a brand new throttle body setup and that the cost was going to be in the range of $1,500 for labor and everything. To be honest, i was not expecting that, but i do know that parts can be costly. Where I am now is just wanting some feedback...ive found threads about the TPS going bad and needing replacement, and some people rebuilding the throttle body assembly (motor and stuff)...and it just doesn't seem like this repair should cost that much based on what I've read.

I'm not mechanically inclined enough to do this repair myself, nor do i have the tools or time, but man would i ever like to avoid that kind of cost around christmas if possible. Any advice from the masses? This is the first major issue we've had with this car and given how well it was running, it just seems weird that the entire throttle assembly would just "go bad" in this nature.

Thanks guys.

LuxuryGS3

iTrader: (12)

If it was your TB motor or lever assy it would throw a code. I just went through that whole ordeal, basically bought a TB with 80k miles with everything on it and car was working again no problem.

If there's no CEL then i'm stumped man. That's usually what helps us get pointed in the right direction.

SC400slide

iTrader: (11)

If it has been slowly getting worse, it could be clogged cats. If the mechanics are family friends, just give them the puppy dog eyes.

LexXxtacy

I noticed you said the MAF sensor is fairly new, Your symptoms sure sounds like a dirty MAF sensor. This sensor detects the amount of air in the engines intake system and, in conjunction with the electronic control unit, controls the amount of fuel supplied to the engine. A dirty MAF can lead to excess amounts of fuel being used, rough idling, sluggish acceleration and reduced power. Cleaning the mass air flow sensor every two years or 20,000 miles will help prevent this problem.

below i put alink for a maf cleaning DIY from a rx300 but it is the same for the gs300, just the 2 bolts.

https://www.clublexus.com/forums/rx-...-cleaning.html

*Also dissconnect your negative battery terminal for 20 minutes.

SeanHRCC

It did throw the TPS code (along with a billion misfires and the O2 sensor)...

I'm a little brain dead today from work, i left out that we towed it to the shop because the car started stalling while driving, and we noticed that throttle inputs sometimes were not doing anything, the car would only idle enough to stay on when we put the a/c on, but it would eventually stall out. The throttle position sensor was replaced with a new one but the problem still persisted (that was done while i was standing there). They also cleaned the MAF and cleaned the throttle body before giving us the bad news.

I have a buddy that does some repair work on the side and he said that his sister had an ES300 that had the same problem and they were able to find a used part and it worked...i suggested that to my mechanic and he said if i can find one he'd be happy to try it out (found one online). I'm hoping to save some money but understand that it may be time for a major repair. She's got almost 200k on the clock so thus far (in the 6 years we've had her) she's been a champ.

Forgive me leaving out that chunk of info...I'm coming off a 14 hour patrol and a phone call that essentially screwed christmas...it's not the end of the world, but it's no walk in the park either (especially this time of year).

GS4_Fiend

iTrader: (22)

A new throttle body is not cause solve the rich issue. Your issue is most likely something else. Make sure your car is in fuel control, have the correct oxygen sensor type, and make sure cats are not clogged. Just to name a few.

2GSKaizen

iTrader: (1)

Do NOT pay that guy 1,500 to put on a new throttle body. That is not the cause! As above, sounds like clogged cats mixed with bad 02 sensors and or TPS sensor. Start with the cheap stuff first, don't start with 1,500 repair and work backwards.

joeyfett

These are the exact symptoms my old Mitsubishi had. Ended up being a cracked head gasket :/

Hopefully that's not the case here