RPMs Drop?

[PaulR]

Hi everyone,

I am having an odd issue with my car. When I am at about 40 MPH or higher and let off the gas, the engine will go to idle speed and then back to the appropriate speed. I have found a video online where the same issue occurs around 1:30:

http://www.youtube.com/watch?v=_C0_JEX7 ... r_embedded

Has anyone has this issue with their Solara, and, if so, how did you fix it?

Thanks for your help!

[chriscarter]

I'm guessing you have an automatic? Check all transmission kickdown cable adjustments. That speed range is about where you would normally be shifting into high, but if the passing gear kickdown cable isn't adjusted properly it can fool the auto trans. Just an thought. Without any more details have to eliminate one suspect at a time.

Has any work been done recently that would coincide with this problem or did it just start happening on its own?

[PaulR]

I'm guessing you have an automatic? Check all transmission kickdown cable adjustments. That speed range is about where you would normally be shifting into high, but if the passing gear kickdown cable isn't adjusted properly it can fool the auto trans. Just an thought. Without any more details have to eliminate one suspect at a time.

Has any work been done recently that would coincide with this problem or did it just start happening on its own?

Thanks for your help. The issue has been happening for a while, not coincided with any repairs. How can I check the transmission kickdown cable? Is it a huge job? My Chilton's manual mentions a throttle cable and shift cable - is this something different?

[PaulR]

I adjusted the kickdown cable just a few minutes ago and, although it shifts smoother then it did, this did not solve the problem. Any ideas to what else I should check? Thanks.

Also, for anyone adjusting the cable, the Chilton's manual mentions to have an assistant hold down the gas pedal while you adjust the cable. The cable should be adjusted with the pedal released, not with someone holding down the pedal. If you adjust it all the way tight, you will have extremely firm "performance" type shifts. The distance between the metal "bearing marker" on the cable and the rubber stopper should be between 0 and 1 mm when adjusted to factory specifications.

[chriscarter]

How long ago were the fluid and filer changed? Your problem may have nothing to do with the automatic, but that's the easiest place to start and eliminate many variables.

Have you noticed whether you get any warning lights or other intermitent signals when this happens? Does the radio change, do the lights dim when driving at night, any jerking or just loss of power?

[PaulR]

How long ago were the fluid and filer changed? Your problem may have nothing to do with the automatic, but that's the easiest place to start and eliminate many variables.

Have you noticed whether you get any warning lights or other intermitent signals when this happens? Does the radio change, do the lights dim when driving at night, any jerking or just loss of power?

Funny you mention a fluid change. I drained my fluid about a month ago and overfilled it by about 2.3 quarts. It released about a quart itself on the top of the transmission and I siphoned out a quart. My dipstick is bent and I have one on order at the dealer to get an accurate fluid reading. However, this issue started before I changed out the fluid in the pan. after adjusting the kickdown cable, I notices it doesn't drop as much at 60 or so as it used to?

Thanks for all of your help, Chris.

[chriscarter]

No charge!

[PaulR]

I just noticed I forgot to actually answer your question. The electrical system is pretty strong, and the lights only dim at night when I use the window switches. There isn't any jerking that I notice. It still does it badly (worse than the video) at 40 or 50. Could this be the throttle position sensor or the idle air control motor?

[chriscarter]

Possibly dirty contacts in the TPS. Wouldn't think IAC.

[Solarizona]

I had the same problem a while back. For me, it was a bad EGR sensor.

[PaulR]

Thanks for your help guys. Is there a way I can diagnose that the EGR sensor or throttle position sensor is bad? The only reason I would not believe it to be the TPS is I don't have any other symptoms and the pedal is extremely responsive.

[1gSE]

back probe the connectors and check voltage

[PaulR]

back probe the connectors and check voltage

Hey 1gSE,

Thanks for your help. I tried a new EGR position sensor and it didn't make a difference. The connectors on the back have some kind of circular insulation I can't remove (I don't think) to probe the connectors with. After the EGR position sensor, what would be the most likely culprit?

[PaulR]

I also found another video that is more like what mine does, except I am not going 80: http://www.youtube.com/watch?v=UoudjgxB2NY

[chriscarter]

Stop throwing parts at the problem and check error codes with an OBD-II reader.