I made a post about something similar to this in past regarding the same car (my '88 Camaro in the sig). However, this issue must be different from what was suggested to be a loose timing chain...

The past couple of days, upon starting my engine cold, the idle speed will initially shoot up to ~2000 RPM. Now, I realize that that's more-or-less normal; ideally, it should slowly make its way down and, once at operating temperature, be idling at ~800 RPM. That's what used to happen on my car. But what's been happening recently is that it will shoot up, and then after about seven seconds, it will go back down to *less* than normal idle--so low that it acts like it wants to die. It will struggle for a second or two, then pull back up to 1500 RPM. It stays there for ~10s, and then drops down to about 1000 RPM... stays there for a few seconds, pulls back up to 1500 RPM. And this is about the point where I realize that I'm running late for school and can't watch it anymore...

This just seems really odd to me. When it's at operating temperature, it's fine (except for a small flutter of about +/- 100 RPM, which is probably due to the high-miles timing-chain). But this behavior seems like it's "deliberate" on the engine's part--that is, it seems like the computer is playing with the IAC valve to change the idle speed, but can't quite "make up it's mind" as to where it want's to leave it.

Any ideas why this might be?

Thanks

BTW -- I've only changed two things on this car recently: I've reset the TV cable setting a couple of times, and I've put a new MAF sensor in it.

 

I think Vacuum leak.
Honest Old Hoses cause so many problems.
ESPECIALLY CHECK THE ONE by distributor base, driver side. It's main PVC connection.
That's a bear to replace.
It's 1/2" short section of good hose.
Rest of plastic lines repair with 5/16" windshield wiper hose.

 

KED85: I know that I've put a vacuum gague on this car before (I just bought one a few weeks ago), and the reading "seemed good". I haven't done it while it was cold, though.. I'll take a look at the one you're talking about.

While we're at it... I've seen a lot of your posts on this board, and you really seem to know your stuff about these engines. So, I'm wondering... I've been thinking about replacing the timing chain--and hopefully smooth out my idle (not to fix *this* problem, but the other problem where the idle flutters all the time). My car has nearly 130K on it and I know the chain has never been changed. I'm fairly comfortable with the procedure (I have some good posts on the subject bookmarked), however I'm still curious about two things: about how much will this cost and about how long will it take (start to finish)?

Those will be two important issues for me because I'm a student (which means not a lot of time or money) and this is my daily-driver (which means I can't be without the car for very long)...

I'm really trying to rid myself of all idle irregularities--something about a bad idle that just makes me think that I'm driving a junker...

Thanks

 

If you go with the double roller chain, it will cost around 120 bucks -- 90 for the chain and gears, 30 for the gasket set and RTV. If you go with a regular stock replacementn it will be about 65 -- 35 for the chain and gears, 30 for the gaskets and RTV

Should take about 1 weekend to do if you start about 8am on saturday and quit at 6pm. finish up Sunday

 

YOu have a project ahead of ya.
Don't do it alone.
Find a friend to HELP GUIDE YA or bite the bullet & pay.
Chain $30 (Dynagear is perfect solution)
Gasket kit is about $20
Goop is $5-7
Fluids is varible (antifreeze oil filer)-$20
Waterpump is $20
Tensioner is $10+
Sleeve for snout is $4
Need new hoses for winter safety, what about belts, too?
Timing replacment project is a very long educated day or so.
And that's IF ya don't mess up.
Do you know how to do this, alone & guarantee success come school on Monday?
Ask at school auto shop if they take on cars & you buy the parts & you learn, too!

We can couch ya, but.....

Be real to help yourself best in the end.
Also look at the distributor rebuild article I made short time ago.
That's a great project, too!

You do have a long road back & it'll be a bunch of nagging long visits under the hood.
It can be done, but,.. frustration is your friend.
Keep asking we'll assist ya.

PERHAPS, is this the right car to own right now?
Maybe, one more reliable & in better shape is your right solution before you open your tool box & wallet.
You do have a long life ahead to enjoy the playtoys of cars, later on, I'm sure. Be real & help yourself the best ya can

 

Sounds like vacuum-ish to me too..or maybe a sensor.. Wonder if his car is switching from open to closed loop instead of staying open on a cold engine like it should be? A buddy of mine with a Saturn had a really bizarre idle..and sometimes his would rev up and hang there on a normal engine temp and everything. He said it was his Throttle Position Sensor. Food for thought!

 

IAC

 

now that i think about it, could be TPS too

 

Didn't think about checking the TPS... I've never checked that on this car. I'll check it out...

KED85: I've actually been wanting to do this for a while now... I'm not inexperienced, and I'm always working my dad who has more experience than I do (been working on cars for quite some time). However, most of our experience is with small-block Chevy V8s. In fact, we completely tore-down and rebuilt the engine in my '89 IROC (in the signature). Although that's a whole other issue (if you're really curious, you can see my other posts in the General board regarding this car--big mess with overheating problems)...

Anyways, when I think of changing a timing chain, I think of how it would be done on one of the V8s. I just had this thought, though... On these V6 engines, isn't the water-pump "intergrated" into the block (and not merely bolted on--but still "separate"--like on small blocks)? I can't really picture it right now, but it seems like that might make things more difficult on this V6 as opposed to doing it on the V8. Mabye I'll see when I get there. Actually, something has been leaking coolant from the front of the block for a while now, and I bet it's the water pump. Might be a good time to knock-out that problem while I'm at it... You mentioned "waterpump is $20". Does that mean I need a whole new pump (and it's just $20?)?

Lastly, where can I find these parts at?

Thanks again!

 

IF you helped on a Chevy small block, then this is the same mission.
Almost identical.
Plan on new hoses, too.
MAYBE EVEN A NEWER Timing cover, as mine was shot due to corossion.
Pump is the whole thing (yeah as cheap as $19 even w/lifetime warranty!). Next is the timing cover as you believe.
Phone around to any place in phone book, let your fingers do the walking.
800-831-0884 Northern Auto is another place to mail order, along with Summit & such.
Give local vendors first crack. They'll bargin better if ya pay in cash.

If ya do the chain, hoses & rebuild distributor as I describe, you be so pleased with your ride.
Like rebuilding the engine for cheap! so strong a difference. It is labor intensive, be aware.
BUT SO WORTH IT!!
I can't say enjoy until the project is done!