Trying to solve idle problem... '97 3.5
Long time lurker, first time poster. Firstly, kudos to the good folks
who run this site and to all of you who give of your time to try
and help others. Well done!
I purchased my '97 Intrepid back about 2 1/2 years ago and,
until recently, it had run like a top. I noticed about 10 days ago
that when at idle, in or out of gear, there was a slight misfire.
Under load the car was acting normal. (No MIL at this time).
Browsing through the posts here I saw others with similar idle
problems and many seemed to think it might be the Idle Air
Control valve. I removed the IAC and sure enough it was
carboned up pretty good. I clean the deposit off the pintle and
re-installed it. When I started the car it ran poorly for the first
minute or so, then started to idle in the normal 700-800 RPM
in P/N and 500-600 RPM in gear. However, the miss was still there
and now the MIL was illuminated.
Key code check returned 12 and 43. I know about 12 and the
Haynes manual addresses the 43 as misfire basically. So I took
the car to Auto Value and had them run the scan tool which
revealed a misfire on cylinder 5.
The car does not see a lot of use, and to my knowledge, had
never had much done in the way of scheduled maintenance,
aside from the regular oil changes I've performed since buying it.
(Had 103,000 kms on it at purchase, has 124,000 kms now.)
So I changed the plugs, plug wires, fuel filter, as well as replaced
PCV valve, PCV hose (was starting to crack) and the air-make up
hose (was split on valve cover inlet). Fired her up, no change.
Yesterday morning was about -18C (0 F) I started the car
and it started as normal initially, then it began to pulse the
idle. Up to about 1200 RPM then down to about 400 RPM,
repeated this for about 5 times over about 30 seconds, then
settled into normal idle. (Still missing though) I have never
noticed this before, it hasn't be this cold for a while here and I
normally do not let the car warm up before driving it. Car still
seems to run as normal under load.
I'm on a limited budget at the moment and can't really afford
to have the car checked out at a dealership, I could really use
some ideas on what I should look at next. All replies are greatly
Thanks in advance.