So I put in a iacv and it helped with the surge upon acceleration( it also seemed like lag). I drove around to get the computer to get used to the iacv. Now while at a stop my Trac off light would appear and the rpms would jump, the code was P0507 which is the iacv. I replaced the factory intake with a short ram(intend to make a makeshift cold air by combing two short rams, so I can switch back and forth on the fly), cleaned the throttle body, seafoamed the car. While the surge is 90% gone the rpm jump at stops when idling still persist only ever setting the p0507 code alongside the Trac off light. A p0171 was thrown once and it is a "too much oxygen entering exhaust system" code. So should I change the harness that connects into the iacv or should I change the throttle body or tb gasket? The way I see it; it sounds like the connector is shot but I have a feeling it could be an 02 sensor as on my scanner in the I/m section it states evap & 02s/h02s not ready. If it is the connector how far down into the loom will I need to go or can I just splice what's out of the loom?

Also while on the subject, anyone use the obx vortex tb spacer for the eco? Yay or nay?

I would check wiring and plug in piece. If all is good take back and get a 3 if still doing it there's another problem. Only the up stream o2 sensor controls motor. If it's throwing a code or really old I would replace. The down stream after the cat is emissions only. I completely blocked off on my 2.2 with no problems. Pull throttle body off and see if it's cracked and check gasket if bad might be letting in air which would cause poor idle. See how those checks go and if still doing post back on here.

Okay so a small update, I put in a new oxygen sensor as well as a new map sensor and double checked all the connections of my intake, vac lines and everything around the throttle body. The problem still persist, the new o2 sensor did bring my rpm closer to 1k where it should be compared to the 2k+ it would stay at. So progress is occurring I will be removing my tb here in a few to clean it and put on a new tb gasket. I have a tps as well that I acquired from upap so I will put that on as well.

For the tb removal do I have to disconnect the throttle cable or can I leave it attached and just put the tb off to the side? Don't want to remove the cable and end up not being able to reattach it or damage it.

Okay another update, I removed the throttle body and sprayed it real good with tb cleaner then once wiped as clean as I could get it I wiped what I could of the plastic manifold then replaced the tb gasket. In my short ram intakes pcv hose I noticed what appears to be white goo which another person on here posted a thread about them having this mysterious white goo as well. I also attempted to swap my tps but alas I was too stupid to figure out how to unplug it and could only remove the entire thing from the tb. I have a video of what my rpms look like when I'm at a complete stop for more than 10-15 seconds. With a new o2 sensor the rpm jump was affected but not eliminate, it before the new o2 sensor would go from 2k & jump upwards but now after the o2 sensor the idle idles at about 1.5k but when the Trac off light pops on alongside a pending P0507 but no check engine light the rpm jump goes from 1.5k down below that rather then higher. I checked my intake to see if everything was properly attached as well as checked all the vac lines I know of to make sure they were okay
It should be noted that and I may be just imagining it but sometimes I think I hear some type of grinding upon accelerating coming from the engine bay. Any who here's the video

https://youtu.be/-08uvm91_Ds

Hi Kamui,

Any chance that the intake manifold is leaking (past the throttle valve)?
That manifold is plastic in that engine. Other cars had trouble with plastic intake manifolds...

Good luck, Peter

No idea if it is but I just got a new valve cover gasket so I'll be checking to see if the timing chain is stretched and while I'm doing this I'll be removing the plastic manifold to check to see if any cracks are present. As for the timing chain how exactly can I tell if it's stretched without a shadow of the doubt? Not familiar with them

It sounds like you have a vaccum leak. Before you take the intake off get a can of carb cleaner and spray every where there is a gasket on the intake, if there is a leak your rpm will change when you spray it.


- Your not-so-local, untrained, uncertified, backyard mechanic. But my @!#$ runs

Didnt think of that, I'll try this method before removing the intake.

So nothing really popped up by doing the carb gasket test, I'm thinking three possible causes. 1 the plastic intake manifold is cracked, brake booster check valve and grommet are bad or head gasket, though unsure if a head gasket would cause this. How does one check if their check valve is bad?

Went ahead and ordered a new intake manifold plenum alongside a booster check valve, is there anything aside from the 7 10mm bolts that needs to be moved/removed? Wire harness or the dipstick?

Okay so new intake manifold has been installed for about two days, has a new maf sensor and an even newer tb gasket. I removed the valve cover and cleaned what little build up there was and replaced all the gaskets including the bolt gaskets. The pending p0507 is still present only when the car reaches half way point on the temp gauge(195).

Throttle cable is not kinked, throttle body appears to have no visible cracks and from what I can tell the butterfly is not damaged. The pcv nipple has been cleaned as well as the hose on my intake and the tb itself is as clean as possible without it being new. The only things left that I have not replaced that I can think of relating to the code are the tps sensor(the clip is not cooperating), evap solenoid, fuel pressure regulator and brake booster check valve.

I have taken photos so I will upload those then post them here for you guys to see, the timing chain is fine from what I can tell. Nothing major seems to be wrong and the only problem is this vac leak. I did the spray test but to no avail, nothing changed. So out of the evap solenoid, fpr, bb and bb cv. Which commonly goes first?

Oh I have a new fuel filter but have yet to install it, will be doing that next.