Lets first start off by saying that I too dropped the gromit into the motor as well and it was a royal pain to get out.....

Anyhow I changed plugs and not much change in performance. PCV change seemed to help a little but no where near what I am looking for in terms of accelleration.

I did not change the coil packs because there doesnt seem to be any misfires. I searched on what a worn coil pack woulc look like and came up short. The springs inside the coil appeared to be in very good shape. Am I just being ignorant in thinking this way?

Wife is going to run some Lucas fuel treatment on this fill up and see if that will make a difference. Car does have 150k on it . Could it be possible that the rings are just worn on the pistions? If that was the case, wouldnt I be seeing smoke? Going to have the front and rear differential fluid changed this week as well.

Thinking about installing a Weapon R intake but dont think that would make a significant change.

My last thought on how to improve performance would be exhaust. Ive been looking for a header for the RX and cannot seem to find anything for it. I do have an exaust leak on the flex pipe where the spring is. So the exhaust will be coming up soon.

I guess next step would be is to take out injectors and either clean or replace them?

Thank you all for your time , input and patience on my questions. That is what makes this forum as good as it is.

 

What exactly are the symptoms? Slow to accelerate? No power?

If your RX300 is AWD, then change out the rear diff, transfer case, and front diff fluid (same fluid as transmission). It'll make a big difference.

With only 150k I highly doubt the rings are worn out (though it does depend on how the engine was treated) , maybe if it was a domestic car they would be.

 

Wow hyper, you are on here as much as I am lol. Yeah Im going to have all the fluids changed this week. Do you need to add an additive along with the differential fluids to the diff?

I recall that you are a fan of redline. I prefer royal. The on site mechanic at wifes work uses nothing but M1 which isnt a bad product at all. The good news was there was no CEL after replacing PCV valve. The old one was still funtional but very grimey. It appeared to be the original one after 150k!!

Could the pcv valve be the culprit in the "sludging" issues on the RX???

To answer your question Ill use this as an example. Whenever I go to get on the interstate it takes seemily forever to get to 60mph on the ramp. I will have throttle wide open and you just cannot feel the acceleration.

After reading the nightmares on here about distances travled on a tank of gas I think she is ok on that aspect. I believe the 99's have a 13.5 gallon fuel capacity. She is getting almost 300 miles out of a tank of gas (with a/c off).

Another concern is the RPMs at 75mph will be near 4k. Is this to be expected on the AWD's?

 

Yup, I can't get enough of CL. Haha!

The RPM's at around 75 seems tad bit high. But, you still have overdrive, or at least it seems you do. Because if it were in 3rd the rpm's would probably be much higher.
At 80 mph I'm at like 3200-3400.

When you get onto the highway, does the RX downshift or is it lugging because it's in the "wrong" gear?

The PCV valve design was a problem in the early versions, the main issue is the holes in the head aren't big enough to allow enough oil. Plus these engines run "hotter" than most. But, with proper OCI these are great engines.

No additives are needed. Unless you have LSD.

 

What octane fuel are you using? The slow acceleration sounds like your using 87 octane?

 

We run Shell 93 vpower. No unexpected downshifts on the highway. I tested the overdrive by disengauging it and all is well. Im gonna do thefluid change, run the lucas and go from there.

The exhaust leak isnt terribly bad. I had much worse. Do you know of any headers made for the RX?

Engine temp is running just a tad over halfway. We took a 700 mile round trip from Indy to KY in high humidity and 95+ degree temps and had no issues with the cooling system.

As for the coils, I would assume that a bad coil would trigger CEL. I read in another thread that you had posted that it could trigger the light but unlikely. The springs on the coils all looked great. Is there any way to test the coils?

 

I think with coil packs, they pretty much work,or they dont. Its one or the other. As far as the headers are concerned, I dont remember what the 01 manifold looks like, but on my 05, it looks like it has header type manifolds on it now.

 

A bad coil will trigger a CEL, but having a misfire, a P03XX code won't necessarily mean it's a bad coil. It could be a combustion issue or electrical issue. As I mentioned I just had a P0303 pending the other night with a flashing CEL, but no hesitation or other symptoms indicative of a misfire (but yet one did occur and that CEL was flashing until I cleared it with my scanner).

A bad coil will continue to be a bad coil (hesitation, bogged down).

I know headers, but not sure what kind of headers you are referring to on the RX300, there's OEM and then aftermarket one for the 1MZFE motor.