FilPilot

00' RX300 ...noticeable surge/stumble when starting from a stop. very consistent and no codes.

Overall love this car, have owned it since 120k, now it has 180k. no problems to report (no codes), millage is 17.9 mixed driving.

I understand there are many areas to start troubleshooting, I am at hoping for some guidance(soundboard) on were to start.

Things I need to do are many but for starters.
Plugs, need to be changed
Timing belt, done at 105, many need one again
All sensors original to the best of my knowledge


Thank you for your input

AnthonyMtz

You need to remove your throttle body and clean it, also clean the IAC valve, if I were you I would also get a gumout engine treatment around 7$ put the whole can through your throttle body via vacuum hose on it, shut it off after wait about 8 hours start it up and run on the highway at 60mph with the "o/d off" button on, dive about 8-15 miles and it should be running smoothly, don't forget to also add a redline gas treatment, made my rx feel so much smoother, o'reilly sells it, not sure if they do elsewhere.

fastnoypi

If you need to do your plugs, now is a good time to remove your intake manifold to thoroughly clean the iacv and throttle body with all the space in the world as AnthonyMtz suggested. You will have piece of mind to properly torque your plugs and can take a visual inspection if you need to replace your rear valve cover gasket and spark plug tube seals while back there. If you have an oil consumption problem, this is also a good time to pull off your rear valve cover and clean out the baffles or replace with the better designed rx330 version.

matts6887

anthony; what type of redline gas treatment is this? Is there more than one type or just one? I ask because i think it might help mine as well even though I havent had any hesitation or stumbling etc.at this point.

FilPilot

ok sounds like good advice. I will do the cleaner thru the vacuum tube. Would love to do the plugs. maybe not right now but will do the Throttle body cleaner, next week keep u posted with results. thks

carguy07

Not in love with the cleaner through the thru the vacuum tube thing. Sounds like a good way to wash the oil off the cylinder walls and scuff them up.

AnthonyMtz

You can google it, it.sold on amazon but I've only.seen it sold inside O'Reillys auto part stores, it is in a tall clear bottle, make sure to buy the gasoline version because they sell a desiel one as well and they look almost identical!

AnthonyMtz

Actually it's through a vacuum hose via the throttle body, my Rx is going on 190k and I've done either a MCCC, seafoam or gumout treatment every 5-8k miles since 140k and I've had no problems with loss in compression or performance, it's helped my mpg's and my engine run smoother.

matts6887

I gotta admit anthony; I do like the sounds of what u are describing in terms of it running smoother etc; but so far It does not seem that i need to do the gumout treatment. However; mine does have over 140,000 with 153,000 and change miles on it; so In the next day or so I might see if i can hunt down some of the stuff u are talking about; cause it sure would be great if i could get a little better mpg out of the ole rx since its got such a smallish fuel tank at only 17 gallons capacity.

AnthonyMtz

Sure thing buddy, the gumout is like seafoam and mopar combustion chamber cleaner, I just get whatever is on sale and convenient lol!

matts6887

I hear that about whatever is on sale! true that!.

10acimport

Did this fix the hesitation ?
I have the same problem and would love an update.

Drcoffee

Look at the MAF. It monitors air flow until you get to WOT. It can be dirty or failed. A quick test is to unplug the MAF and drive around. If its failed, there would be no change in the symptoms.