On Feb 25, 10:17*pm, "Robert Swinney" wrote:
Thanks for the tentative conformation, Bruce. *I have no OBD code reader so I don't know if it is
throwing a code. *The check engine light does not come on. *It did come on one time after heavy
acceleration at freeway speed to get out of a jam. *It stayed on for about 20 seconds and then went
off. *It hasn't come on since, although the low idle miss has gotten a little worse.

Bob Swinney
"Bruce L. Bergman" wrote in messagenews:iv2cq49oeuhlq0tuvlvfdie6svamsdfn7c@4ax .com...
On Wed, 25 Feb 2009 20:06:07 -0600, "Robert Swinney"

wrote:
Our 2004 Pontiac Bonneville GXP has developed a low speed miss. *It is particularly noticeable when
the engine is cold. *It seems to miss only at idling speed and is worse before the engine warms up.
The miss goes away when you load the engine under acceleration. *At only 36000 miles it shouldn't
need a major tune-up. *I am guessing a dirty fuel injector. *Any ideas appreciated.

Bob Swinney

* Silly question number one: *Is it throwing a computer code and
lighting the Check Engine Light? *And if so, what are the codes?

* If it's enough to worry about, the OBD-II computer will notice it.

* Only at idle, worse when cold... *You might be right about a dirty
injector. * Try some Chevron Techron additive in the tank first.

* If that doesn't work, buy or borrow a fuel-rail connected injector
cleaning kit and a can of the cleaning solvent. *The kit costs about
what you'd pay to have it done once, and if you are careful to buy a
decent one it will be good for many years.

* *-- Bruce --

What you want to do, is read out the code.
That vintage, they have temporary codes, that they save, for a while.
You can read out the code with nothing more than a jumper wire, it
will flash the codes out on the dashboard light.

For example, code 23 is two blinks, delay, three blinks, long delay,
repeat...

A problem that it notices, then goes away, it still saves, for a
while.
If the problem is solid, the light stays on. if it gets better, it
goes out, but remembbers the code(s).
I had very good luck, it told me exactly What was wrong.. Changing
that.. Fixed it.
Neat system.