Rough running during warm up only when coming to stop
08-22-16, 02:51 PM
#1
Racer
Thread Starter
Rough running during warm up only when coming to stop
UPDATE: This rough running eventually threw a CEL, Code P0770 Shift Solenoid. I solved the issue by draining/filling tranny fluid 3 times and on third time replacing the transmission filter which was gunked up and clogged. Car shifts perfectly now when coming to stop.
I've got a weird problem with my 97 LS w/ 273k. It has this issue only when warming up to normal operating temperature and coming to a stop. It runs fine at all other times.
When the transmission does its final downshifts when going from 10mph to 0, the RPMs on the tach dip down to almost 200 and then it abruptly bumps up the idle speed to normal, about 750rpm. Each time it does this, you can feel the entire car shudder.
It only does this about 3-4 times until the engine is fully warmed up. When I first bought the car, I researched common problems, and a big one was the coolant temp sensor going bad. I fixed this with one I bought at ORielly since my local Lexus dealer didn't have one that day and I had already taken everything apart and needed to go to work the next day.
Is this a vacuum related issue? a MAF sensor being dirty or would it be due to using an Orielly branded Coolant Temp. sensor over the OEM Lexus one?
I've got a weird problem with my 97 LS w/ 273k. It has this issue only when warming up to normal operating temperature and coming to a stop. It runs fine at all other times.
When the transmission does its final downshifts when going from 10mph to 0, the RPMs on the tach dip down to almost 200 and then it abruptly bumps up the idle speed to normal, about 750rpm. Each time it does this, you can feel the entire car shudder.
It only does this about 3-4 times until the engine is fully warmed up. When I first bought the car, I researched common problems, and a big one was the coolant temp sensor going bad. I fixed this with one I bought at ORielly since my local Lexus dealer didn't have one that day and I had already taken everything apart and needed to go to work the next day.
Is this a vacuum related issue? a MAF sensor being dirty or would it be due to using an Orielly branded Coolant Temp. sensor over the OEM Lexus one?
Last edited by Losiracer2; 10-23-16 at 04:46 AM.
08-22-16, 05:16 PM
#2
Lexus Champion
Check negative grounds
I was experiencing intermittent ghost electrical and electronic issues; low idle, slightly erratic transmission shifts, blower motor running slower with all accessories on when at idle...
The negative grounds on these cars are tired; either from age or use.
Check out this posting;
https://www.clublexus.com/forums/ls-1st-and-2nd-gen-1990-2000/828619-negative-grounding-issues.html#post9592820
Haven't addressed the positive battery cables or the alternator positive cable, but they also require attention.
Resistance and voltage drop creep up on older cars...while ours may not look old, the D.C. connections and cabling may require attention.
The negative grounds on these cars are tired; either from age or use.
Check out this posting;
https://www.clublexus.com/forums/ls-1st-and-2nd-gen-1990-2000/828619-negative-grounding-issues.html#post9592820
Haven't addressed the positive battery cables or the alternator positive cable, but they also require attention.
Resistance and voltage drop creep up on older cars...while ours may not look old, the D.C. connections and cabling may require attention.
09-01-16, 06:04 AM
#5
When was the last time you cleaned the throttle body including the butterfly? I had problem on an older 95 that would die after being on the road a bit when you came to a stop. RPMs would just drop down to zero. Cleaned the throttle body allowing more air to reach the cylinders and resolved the problem.
09-04-16, 10:50 PM
#6
Racer
Thread Starter
When was the last time you cleaned the throttle body including the butterfly? I had problem on an older 95 that would die after being on the road a bit when you came to a stop. RPMs would just drop down to zero. Cleaned the throttle body allowing more air to reach the cylinders and resolved the problem.
09-09-16, 03:09 PM
#7
Racer
Thread Starter
I found out why my car had the rough idle. It was due to a cracked and rock hard rubber intake bellow after the MAF sensor letting in unmetered air.
I went to Lexus and they wanted 87 dollars for one, so I then went to Toyota and asked if I could look for any 4Runner or Tundra V8 boots for comparison. They ended up being too small, I needed a 3.25" coupler about 4.75" in length. Closest I found was a coupler off a 02-05 V6 camry with the 3.0L engine.
Part number is 17882-20161. Original retail cost was 55, but the parts guy helped me out and dropped it down to 35. We actually were able to slide the coupler on with some vaseline moisturizer he had on the counter and a flathead screwdriver. Fitment is tight and its about an inch short, but since it is like a bellow, it stretches a bit.
I went to Lexus and they wanted 87 dollars for one, so I then went to Toyota and asked if I could look for any 4Runner or Tundra V8 boots for comparison. They ended up being too small, I needed a 3.25" coupler about 4.75" in length. Closest I found was a coupler off a 02-05 V6 camry with the 3.0L engine.
Part number is 17882-20161. Original retail cost was 55, but the parts guy helped me out and dropped it down to 35. We actually were able to slide the coupler on with some vaseline moisturizer he had on the counter and a flathead screwdriver. Fitment is tight and its about an inch short, but since it is like a bellow, it stretches a bit.
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