sudden onset rough idle and codes 01 Lesabre


Hero Member
When it rains, it pours, I guess.

01 Lesabre running tip-top, including this AM. Started it up in the afternoon, idles very rough (but didn't stall) and set P0171, P0300 and P0131 codes.

Cleared the codes and it reset a P0171. First job, I know, check all the vacuum lines and hoses. I have the diagnostic algorithm and the AutoEnginuity software to look at some functions, but any hunches?

Wish I had a Tech 2 about now....
only the P0171?
other p0131 is history?
vacuum leak #1 - also a clogged not spraying injector, low fuel pressure, I will repeat low fuel pressure,

use scanner to look at STFT ?
also B1S1 voltage.
start with fuel pressure then the spray trick for vac leaks....


Hero Member
Yep, P0131 didn't reset after I cleared the codes.

Spray trick?

I know B1S1 and STFT and can measure those. But I don't know the secret handshake. ;D
using carb or brake clean- spray suspected vacuum leaks - a change in engine sound rpm will indicste that the spray has located a leak... intake manifold gasket, any Vac lines fittings, pcv valve, hoses.... eespecially related to bank 1.....


Hero Member
And sometimes you get lucky. Rubber vacuum fitting for the EVAP was cracked and came off.

Anyone know where to get these kind of parts? Dealer? It connects the two EVAP plastic hosed to the one opening in the throttle body, sort of like a triple female rubber connector, if that makes any sense.


Hero Member
Dealer didn't have it. I'm thinking there's a creative solution, modifying available vacuum fittings and tubing. For the time being, it's being held together with RTV and zip tie. Eventually it's going to split again, and it's my kid's car; likely as not to stall in downtown Detroit.
without a picture.... :BeatsMe

But the link MAY be searchable ?
Yes, it is about 3/8"......Looks like the line to the f/p regulator has had a "fix" already.....

Cut a piece of fuel hose, should fit over that nipple.....then using Danica's tee, insert it into the fuel hose and then feed the purge solenoid and f/p regulator......if you can't find a tee like that(with various sizes that can be cut off), get a piece of vac line that will fit snug inside of the fuel hose(glue if necessary), and then insert a regular tee into the hose inside the hose...Mickey Mouse would be proud of us...


Hero Member
Yep, there's a nipple on the TB that attaches to the fitting.

The picture I downloaded off the internet; noticed that there was some modification too.

Ridiculous that out of the gazillion vehicles over the years that have these fittings that GM or an aftermarket supplier wouldn't make them available. Searched the entire interweb....the whole thing....and only got the part number and a bunch of sites that once you click to order it, they tell you it's unavailable.

Seems to me that it's a pretty simple thing to remove those parts from their online inventory if the part isn't made anymore; it's not like they're suddenly going to start making it again.

Rant over. Now to get to the brakes and the PS pump....

Thanks for the help, as usual, guys! fixed