ozwin

Have been having some bad idling issues since i bought my car, and have had a hell of a time trying to figure them out. The engine shakes and runs very rough when idling in drive, and when accelerating it seems to stop and start, almost as if the engine is gaining speed in bursts. I know two of the vacuum lines coming from the canister are disconnected, and the lines are capped right past the throttle body as well. Does anyone know if this could be the cause of the issues im having? I have some pics attached below, the engine is pretty rigged up from the previous owner unfortunately.

Travis11394

Mine isn't fully working either but sounds like vacuum lines would be a good repair to work on first. A few of my problems in my car went away once I sealed up a few leaking vacuum lines. Also, looks like you're just one town down from me so if you hear a loud engine idling rough from the north, it's probably my exhaust-less car idling in my driveway, Haha. But sorting out the vacuum lines in the car would be a good first step in resolving your issues. There are a few posts on here with diagrams for the vacuum lines for the V-6 engine.

ozwin

Thank you for the advice! Hopefully both of us get our engines idling right, if not theres always the old LS swap if you're local you should bring it out to a meet in the area sometime, the cruise in at Lowe's in Stuart is always a great time.

Travis11394

I might start doing that once I get it running good enough, however long that will take. Thanks for the heads up!

HellHound

iTrader: (1)

brake cleaner or crab spray, in short bursts to find the leak. be careful the stuff could burst inflames while running. ill be going to a vac block soon on mine. do away with all that mess.

Sierra6

I doubt that tube going into the intake tube is sealing 100%. that could very well be a part of your problem.

ozwin

UPDATE: Issues have been getting worse... im going to buy new vacuum lines and replace soon. The canister lines are disconnected and capped off right now, anybody know what that means?

Sierra6

the lines are so old and dry-rotten that they could be leaking anywhere. at least mine were.

zs&tas

Looks like youve got a whole host of basic maintenance to do , keep at it ! Any full car pics ? Vac leak is a good place to start , that electrical tape job in the intake tube looks horrid !

Sierra6

how high does your car idle? a vacuum leak usually means a high idle.

zs&tas

Sometimes not always imo. Ive had horrendous issue driving with a vac leak but idled fine , guess the iac shuts up as it dosnt need to open .
Just thinking with ya
Def needs a basic service tune up either way

maroe624

Yeah you wanna hook up the lines correctly and look for leaks with carb cleaner. Most definitely have air going into the engine and bypassing the MAF sensor thus causing your rough idle and other issues. I would remove the intake plenum and replumb all the lines making sure there nice and tight. Do a full tuneup on your ignition system as well. New icm, cap, pick up coil, ignition coil. Spark plugs. Spark plug wires. Make sure you have an original ac delco MAF sensor as well. Other brand ones don't work.

Sierra6

Yep, only go with AC Delco for MAFs and ICMs. And even if you have an old original AC Delco MAF, it might be bad.

Sierra6

post deleted- wrong thread, sorry

W.E.G.

If you have rotten vacuum lines, you have to fix that.

Its a real chore to route the lines, especially the thin, hard-plastic lines. You can pretty much count on the hard plastic shattering if you flex it at all.

Here is a link to the thread I started on the subject of dealing with my vacuum lines. I have the vacuum all buttoned-up now.
https://www.thirdgen.org/forums/tech...uum-lines.html