Tip & How-To about Buick Park Avenue

The Looping Idle?

How to recognize when your vehicle is having a vacuum leak. Contrary to many of the ASE professional, vacuum leaks can lead to serious engine performance problems, and even damage if not repaired. However vacuum leaks aren't always easy to spot.

As the article would suggest, a looping idle is the first sign of a bad vacuum leak. This usually occurs when the vehicle is in park and you first start out for the day.
A bad vacuum leak can also leave you stranded, can cause sudden engine shutdown, no start or hard start situations, and in some rare cases, transmission and brake failure, and no cruise control. A bad vacuum leak can also be extremely dangerous when driving at high speeds on the freeway, because of sudden engine failure. Plus cause the computer to seriously malfunction, since highly computerized cars like Buick's heavily rely on proper vacuum compression.

I currently have a Buick Park Avenue with a bad vacuum leak because of damage caused by the mechanics at Mark Miller Buick/Pontiac in Salt lake City, while their mechanics were doing clumsy work on my vehicle . I was very firm with the dealership letting them know I wasn't going to put up with mediocre service, being that I have spent a lot of money in car repair and maintenance at that dealership . In the hundreds of $$$$$$ in fact.

The mechanic tried to force the vacuum hose back onto the central vacuum switch with a screwdriver, ( a defiant no no!) breaking one of the vacuum hoses connection, off of the very rare and hard to find, vacuum switch. The mechanic also only put one of the vacuum hoses on halfway. The number one rule in mechanics, DON"T FORCE ANYTHING, because it can break!

Needless to say I was stranded three blocks from home, because of the vacuum leak, and contrary to the ASE guys popular myth, the vacuum leak created a no start situation, and I had to call AAA to tow it home.

With the broken part, the looping idle has returned and frequent engine stalling is very much a problem.

I finally got aggressive in my speech with the dealership the day I was stranded, who is now making emends for the sloppy labor that was performed on my car.

So again contrary to popular myth, a bad vacuum will cause sudden engine stalling and can leave you stranded anywhere.

Learn to recognize the signs of a vacuum leak before problems become severe.

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1 Answer

how to find out if the intake manifold gasket is bad

Spray carburetor cleaner around the edges of the intake manifold an listen for engine rpm change . If it changes you have a vacuum leak .How does the engine idle , steady or does it try to stall .From your description I'd say that your mass airflow sensor is dirty or bad , temp sensor . Your best bet is to take your vehicle to a ASE certified repair shop an have them diagnose the problem. Where they have a professional grade scan tool to check engine sensor data .

Dec 27, 2015 | 2001 Pontiac Bonneville

1 Answer

how can I identify spark plug coil failure without expensive diagnosis ?

Hi, try reving the engine in nutural, do this in dark garage, you might see a spark leaking from HT leads or distributor cap, Check each lead with a ohm meter, resistance should not exceed more than 8000ohm per foot of lead. If in dought replace as a set.
To check for a vacuum leak, Allow engine to idle, spray a small amount of engine start from a can, around inlet manifold, and any vacuum pipes etc. Any increase in revs would indercate a vacuum leak.
good luck

Jun 09, 2014 | 2001 Toyota Corolla

2 Answers

I have a 1996 Plymouth voyager with a 3.0 liter. engine an it is a v6. My question is it is throwing a p0300 code , of which I am aware it is a random misfire. but they y does it act like my fuel pump is losing pressure. ... replaced fuel pump but light is still on what is my next step.. thanks car stumped

Random Misfires on start up
You can disregard the PO300
& work on the misfire issue in general

Ignition misfires
Vacuum leaks
Egr system
Evap leaks
Exhaust leaks
Spark plugs
Mechanical timing
Mechanical engine wear or damage

The entire engine has to be tested

There is a general long list that can be
shuffled some,but it would take several hours
of testing with professional tools to just find the problems

I only mentioned a few areas

That is what the few ASE Master Technicans with Level 1
driveability skills do

If your dealing with fuel pressure issues, the new pump
runs or it doesn't
If it doesn't, given the vehicles age, I would say wiring
issues on the ground side, anywhere in the fuel pump

Mar 09, 2013 | Cars & Trucks

1 Answer

how serious is a vacuum leak in a bmw 2003 525i

All vacuum leaks anywhere on any vehicle
need to be resolved

Too many areas,systems etc that can have vacuum leaks
& they can have somewhat serious consequences

Mar 01, 2013 | 2003 BMW 5 Series

1 Answer


Very common concern with the Explorer, Explorer Sport Trac and Ranger with the 4.0l SOHC engine! The upper and lower intake manifold gaskets fail, causing vacuum leaks..It can be Extremely difficult to detect these leaks, because they only leak intermittently (usually in the AM after a cold soak)... As the engine warms up they seal back up! Sometimes the vehicle will idle rough, surge or stall after initial start up, then the symptoms will clear after it gets to operating temperature... Usually there will be no driveability symptoms at all, except the engine light coming on and setting lean codes.. The gaskets have been redesigned to correct this concern..

Bill Andrade Ford Master Technician/ASE Master Technician

Sep 22, 2009 | 2003 Ford Explorer Sport Trac

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