Frankie Flores

ok so i bought a 98 civic ex it had idle problems and turned off alot. so i tuned it(cap router plugs wires) and replaced the idle air control. after that it still idled alot. so a friend of mine said the throdle body was leaking air. so i replaced that aswell.... and tuned the idle air control... the car still idles alot turns off sometimes... but the problem is still there.. im tired of going to machanics that dont know there stuff someone help please

HCivExoo

check for any and all vacuum leaks. That is your first priority! if you have to with the car running spray carb cleaner around your Intake manifold and throttle body gaskets to ensure you aren't having vacuum leaks there.

Is this Ex auto or Manual trans? I ask because they had different idle air control valves. Auto has a three wire under the throttle body, manual trans has a two wire on the back of the intake manifold.

There is a thermo valve that has a tube connected to the top center of your IM. You could try and check this valve. Also ensure that your EVAP system is operating normally. There are multiple seliods that control the flow of fuel vapors to a charcoal canister and back into the engine, this can play a role in idle if these systems aren't operating normally.

Frankie Flores

yea its a manual trans
ill look into that thanks.... anymore things to look at other than that?..
and how would i fix a vacuum leak?

HCivExoo

well depending on what leaking you make the leak stop. If it is a hose clamp then tighten if it is a gasket you have to replace the gasket. ensure that there is not a leak going to your fuel pressure regulator either this can cause a rich mixture and idle roughness.

motegicivic

How do you see if the fuel pressure regulator has a leak?

Do you know how to test it?

HCivExoo

just make sure the vacuum line going to the fuel pressure regulator isn't leaking. The fuel pressure regulator is on the fuel rail. The vacuum line is all you have to check.

HCivExoo

Just check the vacuum line going to the FPR. It is on the fuel rail. The vacuum line is all you have to check.

Frankie Flores

i checked it and the line was pinched i got a new hose and put it in still same problem.... im going to check all the gaskets.

1997boostedeg

My car is doing the same exact thing and I have checked all the same things dosent make any sence to me at all.

HCivExoo

If you are 100% sure that you don't have any vacuum leaks then it has to be fuel or spark. I don't think it would be spark since you said that you just replaced a lot for the tune up items in your OP. Could check your injectors, if the motor is high mileage and the injectors are old enough they could be not flowing enough at idle to cause your cut off problem.

How many miles are on the car? Has it been modified, if so what and how? has anything like the EVAP system been removed?