Check 'engine Light' And Poor Engine Idle

[DFSguy]

Your feedback and help is appreciated!

My 1999 Rx300 with 57,000 miles had the ‘Check Engine’ Light came on 2 days ago. Just prior to realizing that the light had come on I noticed that the RX300 started to idle very roughly (vibrations and engine stuttering).

I searched this web site today, to see if I could gather any ideas on what may be happening. I homed in on the issues related to a dirty Mass Airflow Sensor. I thought I would take a shot in the dark and clean the Airflow sensor following instructions posted on the bulletin board. For example, I disconnected the cable harness that contained 5 wires; removed the 2 Philips head screws securing the sensor into the air intake tube located behind the air filter; cleaned the small glass filament with ‘Carb Choke & Throttle Body Cleaner’; Let stand for 5 minutes; gently blew and wiped off any loose carbon deposits and reinstalled. Unfortunately this did not work for me. The RX300 idles rough and the CEL is still on. I DID NOT try to reset the computer by taking of the negative terminal of the battery (Is this required to reset the unit to see if Air Sensor cleaning actually worked???)

I realize that I need to get the Problem Codes. However, I am concerned about driving the car (to Autozone) to get the codes and causing any extensive damage to the engine that may result. Are there any comments from folks related to the risk of driving the car with the symptoms provided? Note that I also checked the following:

1. Gas cap is on tight

2. Oil was last changed 3000 miles ago and is at the appropriate level. (regular oil changes have been conducted

3. Transmission fluid is at the appropriate level.

4. Battery is the original but has had no problems starting and maintains clock setting when the vehicle is not used for several days.

Any suggestions or other ideas are appreciated. I really can’t afford a large Lexus bill these days.

Thanks again!

[SKperformance]

thanks for searching the basic answers and trying them first

i would say to clean the IACV which is discussed in other threads in detail to clean , it will idle normally after depending on the problem

autozone can;t mess anything up as they are only plugging a generic computer to yours to read only the ecu and clear the codes if needed.

[DFSguy]

SK,

Thanks for taking the time to respond. I cleaned the IAVC and the Mass Airflow sensors with no luck. I went to a local auto shop and had a scan the computer contents done. I have a P0301 'Misfire Detected, Cylinder 1 ' (idles and accelerates poorly).

I took the plastic engine cover off and reseated some of connectors to what I think are the spark plug connectors. Again I had no luck.

Any other suggestions on things I can try before I take it to the shop? The RX300 only has 57,000 miles on and the owner’s manual indicates that the plugs should be changed at 90,000 so it appears odd that they would have gone bad already.

Cheers

[DFSguy]

Just wanted to circle back and close off on this topic. My problem ended up being a bad ignition coil on number 1 spark plug. Toyota dealer fixed it for $225.

[RX in NC]

I recommend that you check with your local Lexus dealership and ask for some relief on this unusual problem. With only 57,000 miles on your vehicle, it would not be surprising if they offer you at least a partial refund. It is very rare for a spark plug ignition coil to fail so early and you may be able to obtain what Lexus calls its "goodwill warranty extension" as a result.

Make a phone call or stop in and plead your case - all it will cost you is some time. Good luck.

[Jailor]

Just thought that even though this post is dated a few years, I had the exact same problem with the number one cylinder misfire code and when I replaced the coil pak, she ran like a dream. Same mileage when it occured, coincidently. This forum has been very helpful for me and I appreciate the efforts that people put into their posts

[tmastres]

Just thought that even though this post is dated a few years, I had the exact same problem with the number one cylinder misfire code and when I replaced the coil pak, she ran like a dream. Same mileage when it occured, coincidently. This forum has been very helpful for me and I appreciate the efforts that people put into their posts

Jailor, what year is your RX? 99,00? If the part number on the coil you just replaced is 90019-02234,

its quite possible (likely) you'll experience the rest of the coils going bad in the near future. I went through this same thing, I lost three coils over an 18 month period and after the third failure I bit the bullet and replaced the remaining three.

There's a new part number 90080-19016 and my understanding is that there aren't prone to the same failure as the earlier ones.