Rx300 Bogging Down

[TreasureHunter]

First time post... This is a terrific forum and has helped many times. Need help or suggestions; desperate; wife's car. We've had the 99 RX300 for 3 years. Great car. Just started having issues and codes pop up. Replaced a couple O2 sensors. Then MAF code along with others. Before we could do anything, it's now showing 11 codes. Starts, idles fine. In park, engine revs up fine - no missing. When placed in drive, the car begins to bog down, misfire when accelerating. Check engine starts to flash. Replaced MAF - no change. Could not locate any vacuum leaks. Friend said the throttle position sensor... Any suggestions on how or where to proceed?

[jaswood]

First time post... This is a terrific forum and has helped many times. Need help or suggestions; desperate; wife's car. We've had the 99 RX300 for 3 years. Great car. Just started having issues and codes pop up. Replaced a couple O2 sensors. Then MAF code along with others. Before we could do anything, it's now showing 11 codes. Starts, idles fine. In park, engine revs up fine - no missing. When placed in drive, the car begins to bog down, misfire when accelerating. Check engine starts to flash. Replaced MAF - no change. Could not locate any vacuum leaks. Friend said the throttle position sensor... Any suggestions on how or where to proceed?

The honeycomb structure within your catalytic converter is coming apart, crumbling, and partially or fully blocking the exhaust flow.

[carguy07]

"The honeycomb structure within your catalytic converter is coming apart, crumbling, and partially or fully blocking the exhaust flow."

Or not.

Clear the codes and as soon as the CEL comes on, find out what it is and report back. Guessing maybe a coil is shot. Did you use OE (Denso) parts for the things you replaced?

[EdwardB13]

My car behaving somewhat similarly, but only at certain RPM's. Got to where I could not drive anywhere over 2500 rpm- about 35mph. Changed the TPS, and now can get to 55+ fairly easily, but now have a cap of about 3100 RPM... Would the cat, if messed up, be giving my no problems at the lower RPM's, but then as soon as pass 3K RPM's, bog down?

Eddy ~~~