Idle issue

[nubuilder]

Alright, so I cleaned my TB and cut off the diffuser lip by removing only the TB blade (the TB itself has never been off the truck nor have I unplugged the IAC or TPS; the only hose/line that has been touched is the hose going from the valve cover to the elbow that attaches to the TB itself). I first thought maybe the TB wasn't contacting/closing properly so I loosened the screws on it, moved it a little, then opened/closed the blade a few times before tightening the screws again (not super tight either). I also removed (and unplugged) the MAF and cleaned it too. I thought this might have corrected the issue as it seemed to be getting better.

Well, today the truck has been acting terribly: never idling down when I'm coasting and hanging between 1500-2000rpm.

My troubleshooting thus far:
-I pumped the brakes and the idle changes. I'm pretty sure this means a vacuum leak, but I don't know where. (and the truck wasn't acting like this before I messed with the TB)
-Cruise control works just fine. Holds speed (without going too fast or slow).

I think its the IAC, but again, I haven't touched that. Vacuum leak makes sense, but why would it all of a sudden show up?

I'd just like to point out that I completely removed the TB and MAF from my Z71 2yrs ago and never had a single problem with it whatsoever.


I'm really confused/lost/pissed off-at-the-truck right now so any help would be greatly appreciated (by both me and my blood pressure).

 

[drperry]

Give it a quick once over to make sure you didn't bump anything while you were in there... Make sure all your fittings are on tight and such.

 

[OldCracker29]

If you took the TB off, I'd bet the problem is there. Gasket may be twisted, etc. etc.

 

[nubuilder]

Give it a quick once over to make sure you didn't bump anything while you were in there... Make sure all your fittings are on tight and such.

I will.

If you took the TB off, I'd bet the problem is there. Gasket may be twisted, etc. etc.

I wouldn't have thought to check that, but the thing is I didn't take it off. If I did, I would have replaced the gasket to be on the safe side like I did on the Z71.

 

[OldCracker29]

Give it a quick once over to make sure you didn't bump anything while you were in there... Make sure all your fittings are on tight and such.

I will.

If you took the TB off, I'd bet the problem is there. Gasket may be twisted, etc. etc.

I wouldn't have thought to check that, but the thing is I didn't take it off. If I did, I would have replaced the gasket to be on the safe side like I did on the Z71.

Sorry, i misread your OP. My '99 did what you are describing, and it turned out to be the intake gasket.
What did you clean the MAF with?

 

[nubuilder]

Give it a quick once over to make sure you didn't bump anything while you were in there... Make sure all your fittings are on tight and such.

I will.

If you took the TB off, I'd bet the problem is there. Gasket may be twisted, etc. etc.

I wouldn't have thought to check that, but the thing is I didn't take it off. If I did, I would have replaced the gasket to be on the safe side like I did on the Z71.

Sorry, i misread your OP. My '99 did what you are describing, and it turned out to be the intake gasket.
What did you clean the MAF with?

No problem.
I cleaned it with CRC Mass Airflow Sensor cleaner (gray/silver can) and used CRC Throttle Body cleaner on the TB.


Initial findings show that the rubber elbow that goes from the rubber elbow that connects the plastic tube from the valve cover to the intake "bonnet" (as some refer to it) may be the culprit. I pushed the plastic tube farther into it and it seems to not randomly idle like before. I went to Auto Zone, O'Reilly's, and Advance Auto and nobody had the exact piece. I guess if I want to replace it, I have to go to the stealership.

On a completely un-related topic, I think my throwout bearing is bad/going bad. When I have my foot on the clutch, I hear noise coming from the trans/shifter. As soon as I take pressure off the pedal, the noise goes away. It doesn't matter which gear the trans is in (1-5, R, N) when I have my foot on the pedal. I can only hear it idling (probably because the road/engine noise covers it up). I guess a new clutch and bearing are in my near future along with front wheel bearings, and a fuel pump a little later. Damn bearings didn't even last 130k.
Any suggestions as to brands to go with? Probably just going to stick with AC Delco for bearings and clutch, and Delphi for the fuel pump.

 

[drperry]

Kind of a rattle/chattering/clink noise? Mine had that too

 

[nubuilder]

Kind of a rattle/chattering/clink noise? Mine had that too

Yep. That's it!!

I did the clutch on my old '94 2wd 2.2l and it took me 2 days without resurfacing the flywheel. It was an interesting learning experience that I wouldn't mind doing again if I had the right tools and time.

I saw some of your posts over on ZR2usa. Seems like lifting the cab will help with removal.

What all should I look at replacing? (I really have no idea)
AC Delco 381400 clutch kit
pilot bearing
pilot bushing
AC Delco 386433 slave cylinder (includes release bearing)
resurface flywheel (a new one is $120)
Can I/should I replace the pressure fork?
Just hit me with everything you think I should replace.

When the time comes, I'm going to make a separate thread and hopefully make a nice write-up and parts list. (a parts list seems really hard to find, but there's a pretty good write-up on s10forum)

 

[drperry]

Depending on cost, you might as well replace everything while you're in there...

See if you can track down a Hurst or B&M Short throw shifter... Best thing you could ever do for the NV3500!

If I would've had a few days, I'd have pulled mine... I know I could've made money on it, since they stopped making them before I got mine...

 

[nubuilder]

Depending on cost, you might as well replace everything while you're in there...

See if you can track down a Hurst or B&M Short throw shifter... Best thing you could ever do for the NV3500! The shifter doesn't bother me that much. Makes a nice place to rest your hand too when you're messing with the radio/HVAC.

If I would've had a few days, I'd have pulled mine... I know I could've made money on it, since they stopped making them before I got mine...

Nice parts list.


I'm searching, and guys are talking about replacing seals (some mentioned are the engine rear-main seal, and trans/t-case seals). Should I even try messing with the engine rear-main seal? I really don't want to fWONk something up.