lexiscool

Same here, getting codes for 2 days. Symptoms just as Paticake had written. Dang, wish his pictures were still there. Everywhere I look that talks about OCV does not show an actual location on the engine.

Okay, have resolution. After cleaning the IAVC and not getting a good result, I then clean the MAF and still had codes, however after I disconnected the battery the codes went down to the #2 cylinder misfire. Bought 3 ngk spark plugs (dealer $13.86 ea, Azone $6.99 ea) bought Azone and replaced the #2 #4 #6 plugs accross the front. Ran code check, still the #2 misfire code came up. Obvious now it must be the ignition coil for #2. Price @ part store $87.00, dealer approx. $189.00 So I did the next best thing, went to salvage yard and bought a OEM cylinder off a low mileage salvage for $25.00. Installed, and the RX300 is running like a charmed champion. I think I allowed the tune-up items to go undone for too long. I read the instructions for the sparkplug changes for the rear three plugs, and I found a new tool at Harbor Freight and Tool that will do the trick. It is a new long socket wrench, that is flat and has a t-bar internal twist handle that can reach two of them pretty easily. Gonna get it and try it, later to complete the tune up. When I pulled the #4 #6, they looked pretty good, but #2 was fouled badly. Thanks to the forum and all the inputted knowledge of this area.

Always possible. Most of the time cleaning does the job but once in a while they need to be replaced. There is a way to check to see if the IACV is working properly. I have posted the procedure before. You should be able to find it with a search either on this forum or the other popular Lexus forum. The IACV should keep the RPM's at a correct (approximately 700 RPM, warm) even if it needs a tune up. Have you had the codes read? If not, have them read at AZ or somewhere that reads them free and report back and we'll see if we can't help you further Had the codes read at AZone yesterday. 1...Random cylinder misfire 2...#1 3...#2 4...ICV 5...Throttle Sensor **then repeats of 1-3 I did some reading, and saw that clean the MAF(Mass Air) could be the cause, gonna do that today. Then I was going to do a sparkplug change as well. ($13.78 ea. @ dealer) probably will use Azone denso. I wonder, last week I put in some seafoam for the first time, and now this....any relation??? I've used seafoam in MC before, with good results. I am thinking, maybe it cleaned out so much gunk that it clogged the injectors or somethihing, possible you think????? Thanks a bunch for helping.

Okay....I goofed...apparently I did not read carefully enough to catch that there were two o-rings one on the throttle housing and one on the IAC, found them on ground, put them in and no more leaks........ Huge issue is; I still have the same problem. It is idling rough and going to 500 rpm when stopped at a stop light. Everything is put back just right, the IVC whistle clean, there must be another issue. The CEL (Check Engine Light) is still on, and the horsepower seemed to be diminished along with idling rpm's. BAFFLED....Any thoughts? Tune up with sparkplugs? Does the IVC need replacing?....144000 miles odo.

I thank all for the input for this procedure.... HELP! I must have done something wrong.......I noticed that when I removed the IACV & Throttle body, the coolant fluid just kept coming out from the hose going into the bottom of the IACV...where I had to plug it with a towel. Anyway's after, Yes (stripping a couple screws) I got it off and cleaned it thoroughly. Put it back on pretty good, but noticed when I put fluid back into radiator, it was coming from behind the throttle body......WTH I took the hoses off and electrical connections off and felt behind the throttle body. There is a hole, where something plugs into it.. I don't recall a hose being in there... but it one must go there because the coolant fluid is pouring out of it......I could not find the hose hanging anywhere...any thoughts or diagrams on what is on the backside of the throttle body?