If I drive 75 constantly then I don't feel any jerk. But on a congested day, I have to drive 55-65mph. That's when the car jerks. Everytime I left off of the gas a little and press it again. It feels like the engine cuttoff the gas line momentarily.

Seems like a fuel filter problem but I would think that if it is then I'll feel the jerk at 75mph also.

My car has been tuned up by the lexus dealer a couple of months ago.

Any insights anyone?

 

nevermind guessing, there are too many variables to these cars. sensors, fuel ecu's, relays,. etc...

you could spend 1,500 before you even get close by just guessing and replacing parts. those particular types of on again, off again tech issues are best determined on a machine.

 

I had a similar prob on my LS. Had to do with the idle being aroung 1800 RPM - (55mph) Same thing - let off a little and I would feel (and see) the RPM's drop too quickly and the car felt like a pronounced hesitation. Once I discovered the proper RPM, I could make it happen any time the car was not under load, such as pulling up a hill. Read the posts on Throttle Position Sensor and you may find your answer....

However onelasttry is correct. Could be lots of things. Good luck.

Face

 

i hear that this is normal in toyota cars......once u hit round 60 the car would jerk.....something with the tranny. read that somewhere in like......road and track or some sort of magazine like that. but hey...i might be wrong. mine does that too but i'm not worried by the way.

 

I don`t know what it is, but trust me it is not normal! do you ever get a check engine light?

 

Yeah, it's definitely not normal. It wasn't like this before. I just started noticing it about 3 months after the dealer did the tune up (plugs, wire, rotor, cap).

No the check engine light does not go on. It could be the TPS going bad but I've heard that the check engine light would go on.

I'm gonna drive it until it's very noticeable so the mechanics can troubleshoot it easier. Maybe even cost me more to fix by then.


thanks,

 

No check engine light came on with the LS when the TPS caused my probs...

 

I've noticed a similar problem and my check engine light is on. sensors?
I'm getting it checked ASAP with mechanic. Will check back with results.

 

if its a big jerk, then its ur tps. but if its a lil jerk like the gears are shifting, then i heard its normal. cuz mine does that when i hit 60 and let off the gas, i get a little jerk, as if the car doesn't know what gear to go into. so far, most of the toyota/lexus that my family and i have does the same. is300, gs300, the only one that doesnt is the 4runner. but then again, i might be wrong. u might be feeling a different jerk.

 

qmtran,

I have the same thing happening on my car. When I get on the highway, get up to 50-60mph and let off the gas and hit it again, I get the same thing.

 

Could be the torque converter lock kicking in? It's not a jerk on mine at all, but I can feel it a tad, and the engine revs drop a bit.

 

The only way I can describe it is that it feels like as you're going, you hit an ice patch and the wheels spin for a second and get traction again..

 

Sure sounds like the T/C lock to me. When you take your foot off, it unlocks to let the car coast more freely, then you accelerate, revs go up, then it locks again almost like changing to another gear. I didn't really notice it until I put a decent exhaust on, now I hear it happening often.

 

FYI, I have a manual transmission.

 

I guess it doesn't apply to you then, more some of the others in this thread perhaps :-)
Tried an ECU reset or jumpering the fuel pump?