2000 Rx300 Multiple Misfires

[sdyoung]

Ok, I recently bought a 2000 RX300. Seemed to run well until about 3 days ago. CEL came on. It runs great at idle and revs fine, but when you put it in gear and try to accelerate it pops and cracks, trouble shifting, and has no power. Took it to AA and got 3 codes.

P300 Multiple Misfire

P302 Misfire Cylinder 2

P306 Misfire Cylinder 6

Replaced all 3 front plugs. Light went off, then came back on after about 2 miles.

Checked Coil Packs. Pulled them out, stuck a plug in them and they were all firing.

Pulled MAF, cleaned it with MAF cleaner. Nothing Changed.

Pulled OCV and Filter. Cleaned them and put them back in. Nothing Changed.

Questions:

Is there anyway to diagnose an OCV, or is it just guess and replace?

The CAT Converter seems to be getting hot, Does this get clogged much?

The front of the engine seems hotter than normal, but the gauge shows slightly above the middle, Is this a problem?

Whats next on the troubleshoot list?

Thanks for any and all the help. This is my second lexus but first problems.

[lenore]

You replaced the plugs but not the coil packs? the coil packs break down. Also what kind of plugs did you put in? Hopefully original equipment NGK or Denso iridium. Bosch plugs are a no no.

Replace coil packs on those two cylinders or move number 4 to one of the positions and see if the code changes, if it does then you have bad coil packs.

[sdyoung]

The coil packs were all producing a spark. I pulled each one out, individually, and put a spare plug in it. Started the car and the plugs were firing. Also with car idling I unplugged the coil and it made a difference in the idle so I think the coil packs are fine. Plugs were ngk. I do not know a lot about ocv, is it possible that two valves are stuck and #4 timing valve is still working properly?

[lenore]

Again, don't trust your method of troubleshooting coils, they can act very intermittent. Moving them and see if the code changes would be a better method. The OCV could be a culprit, but generally will effect the entire bank of cylinders. The oil control valve would effect all three cylinders as it changes the cam timing.

[sdyoung]

Ok, switched coil from 4 to 6. Got a bunch of codes.

309,302,304,306,0172,1305,1315,1325

All deal with igniter, 172 is rich fuel.

I expected 300,302,304. Why are all three now showing bad?

I cleared everything. Switched igniter back. Got original codes 300,302,306.

Should I replace all three coils?

[lenore]

I would start with 2 & 6 make sure to use dielectric grease on the connection forfo

Moisture and arc suppression

[sdyoung]

Thanks for the help. I ordered three coil packs. I will install all three and keep my old #2 as a spare. I think the OCV will come tomorrow, I will put that in for kicks.

[lenore]

Don't forget dielectric grease and the oil control valve has a filter screen

[sdyoung]

Got the new OCV today. Threw it in in a quick 10 minutes. Got my hopes up, jumped in the car, fired it up, peeeled out of the driveway. Fell flat !! .. missing and spewing. Guess tomorrow will bring a new day. Three new igniter/coils should be arriving. Next step if that doesn't work.. Sawzall the catalytic converter off. Hope it doesn't come to that, but it might.

[lenore]

Did you check the oil control valve screen....I think the coills will fix it

[sdyoung]

Yes. I took the screen out and made sure there was no sludge. It was very clean. I think the coils may be the way to go. Thanks for your help.

[sdyoung]

Update. 3 new coils. 3 new spark plugs. No change in it. The engine seems to idle fine and revs to 5000 rpms. User acceleration in gear it jumps and pops. 0-60 is not even achievable. What should I look at next?

[sdyoung]

Done a little troubleshooting last night. After the new coils and plugs, I realized car was not shifting into overdrive. I read on this forum that it was a safety feature to protect motor. So I disconnected the battery waited a few minutes, reconnect and tighten back down. Surely it was fixed now and ready to go. Jumped in and everything seemed better. Had more power. Shifted pretty good from first to second. Then at about 4000 rpms in second gear the miss happened again. The CEL did not return, but the miss was there. It did shift into OD though and would make it all the way to 65 MPH. The exhaust seemed really hot coming from the tailpipe and the front manifold seemed more hot than normal, but no overheating on the gauge and no boiling into the radiator overflow. Got an appointment at lexus of Knoxville today, maybe they will have better luck.

[sdyoung]

Cancelled the appointment. The more I drive the rx300 the better it seems to get. Low end power can back first. Still had some trouble during "kick down" getting in interstate. I think it was just hitting the rev limiter. Later took it back to interstate, slammed the accelerator down and it took off. Climbed all the way to 100mph and shifted smooth and drive great. Might keep it now. Only other issue is the clicking in the AC. I added regigerant with oil but clicking is still there.

[Bashir]

I am experiencing same multi misfire codes with my 2000 RX300. replaced O2 sensor on both Bank 1 and Bank 2 and all six coils packs and new six NGK plugs. My engine is running with higher RPM than normal; at 50 mph is 3400 RPM and and 40 mph is 2500 RPM. I took for test drive and check engine light came on within two miles drive. Checked the error codes and now have Misfire on cylinder one with code P301 and P0171. I have not inspected the OCV and need help/instruction in checking it. Can you post some picture of it and instructions so I may remove and examine if it is bad and need to order new one?

What is part number and if can be purchased on line with your recomendations? What is the web site to purchase it?  Any guidance from sdyoung or any pro tech? 

[Bashir]

On September 1, 2015 at 0:38 AM, Bashir said:

I am experiencing same multi misfire codes with my 2000 RX300. replaced O2 sensor on both Bank 1 and Bank 2 and all six coils packs and new six NGK plugs. My engine is running with higher RPM than normal; at 50 mph is 3400 RPM and and 40 mph is 2500 RPM. I took for test drive and check engine light came on within two miles drive. Checked the error codes and now have Misfire on cylinder one with code P301 and P0171. I have not inspected the OCV and need help/instruction in checking it. Can you post some picture of it and instructions so I may remove and examine if it is bad and need to order new one?

What is part number and if can be purchased on line with your recomendations? What is the web site to purchase it?  Any guidance from sdyoung or any pro tech? 

 

On September 1, 2015 at 0:38 AM, Bashir said:

I am experiencing same multi misfire codes with my 2000 RX300. replaced O2 sensor on both Bank 1 and Bank 2 and all six coils packs and new six NGK plugs. My engine is running with higher RPM than normal; at 50 mph is 3400 RPM and and 40 mph is 2500 RPM. I took for test drive and check engine light came on within two miles drive. Checked the error codes and now have Misfire on cylinder one with code P301 and P0171. I have not inspected the OCV and need help/instruction in checking it. Can you post some picture of it and instructions so I may remove and examine if it is bad and need to order new one?

What is part number and if can be purchased on line with your recomendations? What is the web site to purchase it?  Any guidance from sdyoung or any pro tech? 

 

 

[smarkley03]

On 8/18/2013 at 7:38 AM, sdyoung said:

The coil packs were all producing a spark. I pulled each one out, individually, and put a spare plug in it. Started the car and the plugs were firing. Also with car idling I unplugged the coil and it made a difference in the idle so I think the coil packs are fine. Plugs were ngk. I do not know a lot about ocv, is it possible that two valves are stuck and #4 timing valve is still working properly?