I was the one who had the 98' Pontiac Sunfire that was making insane
grinding and squelching noises on startup. Brought it in and it was a
failing Water Pump... a six hour job that ended up being around $700 at
the mechanic.

After I got it back it had a real bad idle (started after their work).
They chocked it up to a totally unrelated 'issue' with leaking oil
fouling the plugs and causing it to misfire. Well I put in brand new
platinum plugs and it still idled bad right off the bad (obviously not
enough time from the small oil leak with the valve cover/gasket to get
in and foul the plugs). I had brought it back into them and they chocked
this up to the oil/plugs and not anything they could've done with the
new waterpump they put in.

The idle is like this: when at stop and in drive or park, the engine
will sound fine and then kind of chug and cause the car to vibrate
pretty bad, and then it will right itself up again and just circle the
pattern. It's a very distinct succession... it will chug for three
seconds or so and then right itself... rinse and repeat. Actual driving
and performance seems relatively unaffected to me

Some good mechanic friends of mine (who helped me replace the plugs and
check out that situation) said that something is definitely off, and
it's not oil fouling the plugs. They said the way it sounds and acts
that timing is off.

So my question: when they replaced the water pump would it had been
possible to mess up the timing while they were at it? Obviously if that
is the case they are not owning up to the responsibility so I need some
knowledgeable outside opinions. Thanks for your help anyone.
--
Shinnokxz - http://www.coryhansen.com

Shinnokxz wrote:
Well for a shop that charges $ 100/hr that is poor to say its due to
oil on the plugs (I'm figuring tax and a rebuilt pump came to about $
100 of your bill.) If it didn't do this before the water pump, then
something may not have been assembled right at the shop or something
was broken. 6 hours seems a long time for a pump on a 4 cyl, IMO.
Take it back and have them scan the PCM for codes, let them take it out
for a drive and capture the data realtime. That should tell them what
the problem is.

Keep in mind, this is a 98 with OBDII, so reading the PCM real time is
not an issue. IMO, this shop seems to think its 1968 and can pay for
their winter vacation or the owners new boat out of your wallet.