jharris400

I have had this problem practically for as long as I can remember with my 01 LS430, I bought it with 186k and now it has 223k miles.

Starting off from a complete stop is usually when I experience this problem. 1st, 2nd, and 3rd gear shifts seem normal but the 3rd to 4th gear shift happens too soon, bogs the engine down, then immediately jerks into a lower gear and accelerates normally.

I have drained and filled the transmission fluid 3 times with T-IV over the time I have owned the car now the fluid is bright red. When driving the car aggressively this problem never happens, only when casually driving and always when going up hill. No check engine light is on, but will it turn on for transmission problems? I just thought about it I've never tried to check transmission codes I'll do that tonight.

YODAONE

Have you performed throttle body and air mix path cleaning?

The transmission follows engine and input from engine sensors via ECU.

What engine maintenance parts have been serviced?

Numerous engine sensors...

The A650-E transmission employs numerous fluid solenoid valves and fluid temperature sensor on wire harness inside transmission.....

jharris400

Yeah throttle body has been completely removed and cleaned even the small ports on the top, it wasn't all that dirty. When I bought the car it was much worse I discovered it had the wrong MAF installed, I bought a Denso unit off rockauto. I've replaced the spark plugs, TPS, and of course the timing belt/wp/pulleys/tensioner/seals. I've adjusted the TPS to all points in the range the service manual gives, between 14.4 and 16% IIRC, that doesn't help. It seems like running with the ETC power mode it helps.

I'm going to go out during lunch with my techstream and look for transmission codes.

No codes or anything out of the ordinary.

Striker223

I had this exact issue on the 2-3 shift, I recently switched to a tuned ECU from All4swap and it completely corrected the issue as well as gave 5 more average mpg, 30hp at least and massively improved PWR mode throttle control and shifting sensitivity.

The stock computers simply get old after a while and have glitches. Let me clarify and mention I tried everything you did plus new VVT solenoids and new factory O2s and a bunch of other services and little things to try and get it to smooth out but it didn't help.

Mine is a 02 217k

jharris400

Wow thank you for replying I figured I'd never find someone with similar problems. You may be right about it being the 2-3 shift, usually when it happens I'm not couting the shifts in my head so I guessed 3-4. I wonder if this could be a capacitor problem? I can easily replace the surface mount caps.

I saw your ecu tune post in your thread, that's interesting what was the down time while you waited for the ECU?

Striker223

Im not sure since the issue wasn't fixed it served as an excuse for me to buy a spare ECU so my down time was zero. Just swapped them and the car was good to go after the immobilizer relearn

repairmatt

Interesting thread, I have had the exact same issue since I bought my 03, it had 233K miles then and now has 247K. It has always been a little annoying, but for me it only happens under light throttle application, under moderate throttle application it will shift normally. Still haven't figured out the cause, but a malfunctioning ECU does make sense.

jharris400

Yes same for me driving like a "grandpa" really makes the problem come out. I bought a spare ECU that I will try out.

jharris400

I'm still experiencing this problem. I have tried another used ECU and had my original ECU tuned by all4swap. The ECT Power mode becomes almost unusable is normal traffic. When taking off from a start 1st gear is fine but once it shifts into 2nd gear it's like I pressed the gas pedal half way down even though I haven't touched it. I've been told that is a sign of a bad ecu but all4swap didn't give any indication on what was wrong or how to fix it. I have checked the capacitors with an ESR meter and even replaced some of them without any difference.

I think I will try another ECU just for the fun of it but instead of 89661-50550 I'll get the replacement 89661-50552.

funcrusher

Highly suggest checking out Relentless Motorsports. I wouldnt let anyone else touch mine when it’s time to fix it

jharris400

I can put paint dots on components and scribble my name on the case just as well as the next guy.

ls430w140

Your issue has nothing to do with ECU. I would suggest looking at transmission input and output shaft sensors, TPS, or other sensors that may supply incorrect (or laggy information) to the ECU. Keep in mind that sensor may not necessarily generate error codes.

teaa

have this same issue on my 2002 with 116k miles, happens in the 2-3 shift range

jharris400

Thanks for the suggestion. I did a transmission drain and fill with T-IV over the weekend and pulled the O/D clutch speed sensor thinking it would have metal debris stuck to the magnet. To my surprise the sensor was clean maybe one small flake of metal on it.

I didn't bother to look at the vehicle speed sensor I guess I incorrectly assumed that was only used for the speedometer. Thank you for the suggestions on the ecu not giving a code I wish I had removed the rear sensor now. If I get desperate enough I will replace the sensors.

As a note I replaced the throttle body TPS with an OEM one a few years back and the MAF with a denso unit bought from Rockauto. So far with the new ecu I haven't noticed the upshifting problem, but usually with the old ecu I didn't notice the problem until a week or so after removing power to do a reset.

funcrusher

Oh okay cool.