citycruzer

Hello,

I'm new to the forum. I have problem with my wife's RX. It was running very rough at idle and acceleration was not good so i took it and had the plugs changed and the intakes (i think they are called) cleaned.

At first when we left the shop it ran so smoothly. However after driving it on the freeway, it developed a rough idle but not as bad as before and a new issue with a hesitation or skip in rpms at idle. As i said, this is a new problem that developed after the new plugs went in. The only problem it had before it went in was a very rough idle...so bad that the rear license plate and the center console rattled annoyingly.

Here are a few of my observations.


Hooked a scanner up to it and there are no codes stored.

Seems that the problem only happens when the A/C is on. If the A/C is off, it holds idle well (still a little rough) but no hesitation or skip/drop in the rpms.

If I had to guess, I would bet that the ECU is making some sort of adjustment at idle.

When the car comes to a stop, it does not immediately start the idle drop/skip problem. It takes about 15 seconds or so to start.

The car runs fine with no hesitation or oddness at freeway speeds but seems to lug getting up to speed


Any idea what the problem is? I'm guessing that many will say its one or more of the Oxygen Sensors. But is there a way to isolate the bad sensor?

Thanks in advance!

citycruzer

boy! It really pays to start with the inexpensive fixes first. Put a whole bottle of Techron in the tank and did not even make it three blocks before the problem started clearing up.

Took it for a drive on the freeway and its getting better and better. Hardly hear or feel it idle and when the A/C kicks in, it hardly effects the rpms.

Case closed!

salimshah

Glad your problem is solved.

Welcome to CL.

Please read the stickies ... RX300 mega thread, Having problems ...

Was IACV cleaned? If not read the DY.

Salim

kalali

I sure hope the case is closed but I find it hard to believe that the Techron was the solution, especially after only driving three blocks. It takes much longer for the mix to go through the fuel system.

hypervish

I have a feeling the tech cleaned the throttle body and related, but did not reset the ECU. And, so while the ECU re-learned values the car drove like crap. IMO, Nothing to do with the Techron. Even my theory is a shot in the dark...

GSGenesis

Don't believe it for a second.

GSGenesis

Oh yea, lol!!! 2 posts, this being them, this guys a rep for sure. 3 BLOCKS!!! HAHAHAHAHAHA!!!!! IM PEEING LAUGHING!!!!! I WISH THERE WERE A CURE IN A BOTTLE BESIDES PAIN MEDS HAHAHA!!

https://www.clublexus.com/forums/sho...d.php?t=662865
I would say a good start there...

citycruzer

Sorry GS, but I am not a rep. I have nothing to do with the Automotive industry at all. interesting responses I've received from this post when all I was attempting to do was share something that helped me out.

The car was running very rough so took it to have the plugs changed because It has 167K on it and I don't remember ever changing them. When I saw how difficult it was to change the rear plugs, it was obvious to me that i never changed them and i do the work and tune ups on all my vehicles. They wanted to charge me $92 for the cleaning and I opted not to do it.

However, I did not have the bucking acceleration problem before the new plugs went in so i took it back to have it cleaned (because they told me the new plugs are requesting more fuel).. did not help at all.

I parked it in the driveway, unplugged the negative battery cable and drove it to Autozone. Unplugging the cable and resetting the ECU had no effect. I bought the Techron (because i heard about it on this forum.. probably form a rep) poured in enough to treat 20 gallons, and within 3 blocks like i said, problem solved.

This is my wife's car. My truck is a 1996 7.3 Powerstroke and i swear by Lucus, rotella, and Mobil One. So i guess I'm repping all brands?!?! Geez!

Now, if you know anything about working on you own vehicles, you know to take the least expensive paths first. Seemed like a $13 fix was better than chasing down $150 sensors or taking it back to pep boys when they were already starting with a substantial parts list.

I don't have an answer to why it worked so fast, but I've seen Lucas work just as fast on my diesel injectors on my 7.3. so go ahead and take the expensive route first if you wish. Those of you that want to chance a simple fix, try what i did. It worked and is still working. No sign of the problem again..

if you still doubt me.. I'm a member on a number of forums.. check to see if I've EVER recommended ANY product. I use the same handle on Ih8mud (for my 99 100 Series Land Cruiser), TheDieselstop, Fourdoorbronco.com, powerstroke Nation, etc... for my Four Door Bronco

RX300CE

Cruzer,
I believe you, I had the same problem hesitation and rough idle because after I pump gasoline that had been contaminated with water (cheap gas station) then I put one bottle stp gas treatment problem solved, like you said take the least expensive paths first .

kalali

Nobody doubts your experience. My comment was about the belief that adding Techron to the fuel was the solution. I've been using Techron since 1985 in all the cars and FI bikes I've owned since and do believe its a good preventive product for the fuel system. All I can say is I've never had a fuel system related issue with any of my vehicles.
By the way, throttle body is not in the fuel delivery path, certainly not in the RX or other port injected vehicles.

timmui

What is the purpose of the PCV system and where is it located in relation to the throttle body?

kalali

Not sure if I follow. What does PCV have to do with fuel delivery? Just asking...

timmui

I can't explain it better than this: http://auto.howstuffworks.com/positi...ion-system.htm

To summarize, fuel vapor blow by gets into the crackcase and the PCV system recirculates that vapor into the intake before the throttle body.

kalali

Trust me I know all that. Fuel vapor is not part of fuel delivery system. That's a by product. May be we use a different set of definitions. Either way the OP is happy and that's what counts. I have nothing more to add.

salimshah

Showing my age here ....

If you remember the smell when you opened the hood of a pre 1990s car, you get a whiff of fuel fumes. These fumes were the unburnt vapors that made their way to the top of the engine (valve cover). Engineers, plumbed the top of the valve cover back to the air intake. Cute thing is that the suction of the intake creates a low pressure zone and that helps suck the fumes from the valve cover and they added a check valve to prevent fresh air going the other way.

It was win, win, win situation for emission, eeking out more mpg and engineering marvel.

Differences are in semantics.

Warning Salim getting on a soap box:
You guys know my position on the valve cover redesign and oil consumption. To me the engine oil can not get high enough to be sucked in the air intake through the PCV. Hot oil vapors can but not a quart worth of oil in 500 miles? If it works for you, it simply works for you, but it does not add up for me.

Salim