Idle issues on a 95 Monte Z34

[Bonzai]

Ok, first of all I'm a noob. I apologize for stupid questions that I may ask now or in the future.

My dad has a 95 z34. Lately it's been idleing erratically.When it's cold it's at it's worst. It will barely turn over and when it does it can barely hold an idle. It fluctuates between 300 and 1500rpms until warm.

I just gave it a basic tune-up. (Plugs, wires, air filter) all of which were shot. My dad doesnt maintain his cars very well. Anyway, that helped a little bit with performance but the idle problem still remains.

I spoke with a friend and we agreed it's either the EGR or IAC. I'm not too familiar with the layout in the engine bay of this car so I'm trying to get as much info as I can before going at it.

My three stupid questions:
-Where is the EGR?
-Where is the IAC?
-How difficult are both of them to change?

Thanks for the help guys. My dad and I appreicate it.

[Juglenaut]

Vac leak or the dreaded lower upper intake leak problem.

[Bonzai]

Vac leak or the dreaded lower upper intake leak problem.

Any common areas where there is a vac leak?

Also, can you elaborate or point me to a thread on the intake leak problem?

[bud36light]

Your lower intake gasket is probably leaking. First remove the plenum. Just cut the TB coolant loop hose. Its just a piece of 3/4 heater hose and needs replaced anyway. Then unbolt the fuel rail and CAREFULLY pry the rail with injectors out and flop it over to the side. No need to disconnect the fuel fittings. Then remove all the intake bolts(there is a couple of bolts that are hard to see). install the new gasket and put it all back together again. Might want to spend the 15 bucks on a Haynes manual too. Also if its got over 60-70000 miles on it replace the timing belt. This will help the idle out also. As far as the IAC and EGR Id try using GM top engine cleaner first. Then try the gasket change. If you need more detailed info just post back. Somebody here will help.

[Bonzai]

Your lower intake gasket is probably leaking. First remove the plenum. Just cut the TB coolant loop hose. Its just a piece of 3/4 heater hose and needs replaced anyway. Then unbolt the fuel rail and CAREFULLY pry the rail with injectors out and flop it over to the side. No need to disconnect the fuel fittings. Then remove all the intake bolts(there is a couple of bolts that are hard to see). install the new gasket and put it all back together again. Might want to spend the 15 bucks on a Haynes manual too. Also if its got over 60-70000 miles on it replace the timing belt. This will help the idle out also. As far as the IAC and EGR Id try using GM top engine cleaner first. Then try the gasket change. If you need more detailed info just post back. Somebody here will help.

Alright, I'll try that next time I get my hands on the car.

One question about the plenum... I got most of it off the last time I worked on it. Only enough to lift it up about 2 inches or so. I got the rear bolt off on the driver's side and all of them on the passenger side. It seemed something around the intake was holding it down. I also disconnected the intake tube so that it wasnt catching on anything. Any advice on that?

[GPXSS]

the coolant hose connection underneath the TB area usually has a death grip between the lower and upper intake.. as Budlight said, just cut this hose. Its about 2" length of 3/4" heater hose, you can get a replacement anywhere that sells hose in bulk.

[Bonzai]

the coolant hose connection underneath the TB area usually has a death grip between the lower and upper intake.. as Budlight said, just cut this hose. Its about 2" length of 3/4" heater hose, you can get a replacement anywhere that sells hose in bulk.

Ok, that sounds like the culprit.

If I remember correctly, that's like a 2in section of hose directly under the throttle body, right?

Again, sorry for stupid questions guys. I just like to know what I'm in for so I dont cut anything I'm not supposed to.

[bud36light]

The gasket can stick sometimes but if you can wiggle the plenum its the tb loop hose. Get a long sharp object and cut the bugger. It is for sure a PIA. If you have a digital camera they work great if you are worried about putting things back together.BTW the IAC is on the TB and the EGR is located next to the cowl weather stripping. It has three solenoids with a wire attached and a pipe connected to the rear manilfold. Oh, you did disconnect the brake booster hose off the rear lower part of the plenum right?

[93GTP]

the coolant hose connection underneath the TB area usually has a death grip between the lower and upper intake.. as Budlight said, just cut this hose. Its about 2" length of 3/4" heater hose, you can get a replacement anywhere that sells hose in bulk.

And when re-assembling this, use a regular screw type hose clamp on the upper connection to the throttle body (uim). It will make things a hell of a lot easier. I can now get at mine with an 8mm socket and an extesion instead of cursing and swearing trying to use a set of pliers on the original clamp.

[bud36light]

And when re-assembling this, use a regular screw type hose clamp on the upper connection to the throttle body (uim). It will make things a hell of a lot easier. I can now get at mine with an 8mm socket and an extesion instead of cursing and swearing trying to use a set of pliers on the original clamp.

DO THIS!!