Vac issue?

[_lithium_]

Ok, I posted here a while ago and thought I solved this issue by cleaning the entire throttle body and replacing the TPS but this issue is back and this is what is happening:

My (92 V6 MX-3 GS) keeps surging on idle. When I was sitting at a red light again, I had the car in first gear (does this no matter which gear it is in btw) and had my foot down on the clutch of course, and my idle would go up to about 1,100 or 1,200 and then plummet to about 700 and keep repeating over and over. This issue doesn't happen however when I am sitting there with the car out of gear at a red light.

I have looked at my hoses and don't see any visible cracks or anything and am completely stumped. Any ideas? I'd be willing to try almost anything.


Also, Does anyone know why my car would (when it has been sitting for hours) always start up and have to high-rev like 2,500 for a while to get warmed up? It's f---ing annoying and I have no idea how to fix the issue but it does it for a minute or two then slowly starts to work its way down to about 1,000RPM

[Nd4SpdSe]

PCV Valve

[_lithium_]

Hmmm, I'll spin by the auto place tomorrow and buy a new one tomorrow, why would that cause this though?

[muttpower]

Have you tried resetting the idle??? I had the exact same issue with mine but I cant quite remember what the fix was right off hand, aside from resetting the idle. I'll post back when I remember.

[_lithium_]

No I never did even think of that, If you (or anyone else) knows how I'd love to give it a whirl! lol

[_lithium_]

Nope, wasn't the PCV valve. I also noticed that all my coolant is going into my reservoir (it is COMPLETELY full) and I turned my car on and put it in gear and when it builds up pressure or whatever, it starts to drip (solid line drip though) out the overflow valve on the reservoir cap. I'm completely lost at what the f--- is going on. I've looked for any leaks and cant find anything

[_lithium_]

Okay...I'm seriously looking for any help at ALL. I've been dealing with this issue for so long and it's annoying the hell out of me. So far I've replaced:
1. PCV Valve
2. (13 PSI) Radiator cap (the one that sits on the plastic housing in front of the radiator, not the radiator fill cap)
3. Reset my ECU


My car STILL surges...WTF.

When I come to a stop sign, put it in first gear, it's rev goes to roughly 1,200-1,300 and then I hit the brake it goes up to about 1,400RPM-1,500 RPM and then plummets to about 700 RPM and then goes back up to 1,400 and back down and keeps going. PLEASE give me some ideas as to what this could be? I've replaced the TPS awhile ago and it didn't fix anything and I cleaned the IAC and Throttle Body which both looked great.

[muttpower]

This may sound wierd, but I remember how I fixed my issue....are you ready for it....I took a stethascope and listened around my intake manifold for any possible vacumn leaks, and ended up finding that my Throttle body gasket was leaking....a new gasket later, and it was fixed...no guarentees, but that's what fixed mine

[_lithium_]

Hmm, I'm gonna use Carb Cleaner to see if I can find any vac leaks (found a reference saying you spray it on certain vac hoses and parts and if the idle gets rough then you found a leak), but why would the car do this predominately when I brake? sometimes i can have it in gear and it doesn't do it, then i press in the brake and the rpm goes up and i let the brake go then it starts dropping and surging.

[Daninski]

I'm offering free K8 intake gaskets 'if you need them' you just pay shipping.

Did you adjust your TPS?

[Ryan]

The flammable spray thing isn't really the best way to do it... it doesn't always work and its a little dangerous.

your eyes and ears and hands are the best, look for cracks and wiggle stuff and listen for a difference.

[_lithium_]

Yeah I'll attempt to just listen for it or look this weekend. Now I never adjusted the TPS because I never knew I had too. I simply screwed the thing on there and went, how do I adjust it?

[Ryan]

http://www.mx-3.com/phpBB3/viewtopic.ph ... and+adjust
and
http://www.mx-3.com/phpBB3/viewtopic.ph ... and+adjust

Don't just mess with stuff, that throttle screw is factory set, and the car will compensate against you unless you do it in DIAG mode.

[_lithium_]

I didn't just mess with it, i screwed the butterfly screw to adjust the idle down to 700RPM but wasn't in DIAG mode (a long time ago) and I am not opposed to giving the TPS adjustment a try but can't imagine this would cause my issue seeing as the idle is fine when sitting still and not in a gear. It's only happening whenever the car is put into gear and tries to increase RPM it seems like. (but can't feel any difference while driving or holding idle still during drive)

[_lithium_]

So I unplugged my IAC and drove my car, the idle didn't do anything. Even after putting it into a gear, the idle remained at 800RPM~ and the car drove a bit rough (as expected) but not terrible. After I plugged the IAC back in, the idle surging happened again.


The thing that is getting me is I noticed my brake fluid cap is cracked bad to where I can see through a small 1in crack all the way through the cap, could the surging only during braking be happening when losing brake pressure or someshit?

Also, inspected for any vac leaks and turned up nothing.