Stickonleg

So my sisters Rx300 was havin an issue where it would seem like the OD was not engaging (was running up around 4k+ rpm at highway speeds) and would seem to get stuck in the rpms as it approached 2k, then slingshot you forward once it finally got above 2k. Said the CEL was on due to an issue with the 02 sensor but would start flashing if she drove it long enough. One day she tried to go up an overpass and the engine just completely bogged down, would barely climb the hill and only really see an increase in rpms once it got to the top and was on the way down and would not accelerate past 35mph and about 1500-2000 rpms.She also said that the trans only wanted to shift once she let off the throttle.

I offered to go ahead and replace the sensor ( which someone had attempted to strap in place with a hose clamp bc they snapped one of the studs) and was able to get it bolted on, though only on one side. While I was doing this I opted to replace both the A/F sensors and the VVT solenoids as the car is over 200k miles and the oil was black. Now my understanding was that you need to reset the computer by either pulling the EFI and ECU fuse or the Neg terminal on the battery when changing the 02 and A/F sensors. I did so and then took it for a test drive and was able to make it over the hill but not really with much improvement.

As I pulled into a parking lot to turn around, the engine stalled out twice, once in drive, then once in park both while at idle speeds. Managed to get the car to stay on by shifting into reverse. Havnt had an starting issues since then, but I received a P0110 code. The scan tool I was using said that the issue was likely the MAF, so i pulled it and cleaned the wire.

The next day I drove it to work with my scan tool going and got a new code in place of the 0110 code, P0172. Replaced the MAF and reset the computer again so that it could unlearn whatever adjustments it had made and took it for a test drive. Was able to drive it much farther away this time, and had a much easier time climbing a hill, but the car eventually just reverted back the same driving pattern of not wanting to accelerate or shift after about 5 minutes of driving though it isnt showing any codes.

I should also note that while i was test driving it, the car seemed really loud, as if it had an aftermarket exhaust system but I cant quite locate the sound's location.

At this point I am unsure if the computer needs a bit more time to relearn OR if there is another issue somewhere that I need to check into. Any suggestions are greatly appreciated.

salimshah

Lot of info, but it needs to be processed.

There is fuel metering issue and misfire (flashing CEL).

Cleaning the O2 sensor can work most of the times, but the sensor can go bad too.

Misfires can be due to plugs/coil, you really need to check the condition [110K miles replacement schedule on plugs].

If you have been running rich [including misfire -- unburnt fuel in exhaust], you catalytic convertor may have been running overtime. That can lead to break in the casing of the cat. There might be a leak/crack in the flex exhaust fitting.

You may have to share live data with folks/mechanics to see what else is going on.

Lastly, I would say do the visual, do the upkeep (plugs, filters, oil), logically follow the error codes. There is a catch 22 on upkeep as some may suggest, fix the problems first.

Salim

Stickonleg

Got these today just like you said.... Will look at the plugs and coils later today once it cools off.

The VCT the scanner is suggesting, would it be referring to our vvt solenoids?