Here are the details:
98 Mystique Sport V6
Bought less than a month ago used, private sale.
Two weeks ago, went on a highway trip and the day after we got back started the car and had very rough idle. Cleared up after a little driving.
A week later, again after a highway trip, it did the same thing.
Then, without a highway trip, but the weather has gotten very cold (-20c) it takes 15 minutes to get the car to run, albeit at a very rough idle.
Starting routine:
1.Turn the key .... car revs to 3000rpm
2.revs drop to 500, car almost stalls
3.revs climb to 3500
4.revs drop to 500
5.repeat 2-4 several times
6.car eventually dies.
7.start at 1 again
Finally the car seems to warm up enough for it to stop hunting idle, but still very rough, and I can hear what sounds like backfires through the intake.
Pulled the plugs and they are very black (replacing with Autolite DP and new wires).
Cleaned the IAC.
Checked vacuum hoses, no visible problems.
Tested EGR ... seems to be ok
Also, found a hose that is connected under the battery (if you look straight down just to the left of the battery it is connected to a nipple on something black) but the other end is free. I have looked everywhere for where it might connect, but so far am stumped.
One more piece of info .... since it has been so hard to start the brake boost power is lost quickly. If you depress the pedal, let up, then press again when coming to a stop there is no boost (vacuum) left.
Leads me to believe some sort of vacuum leak, but I'll be damned if I can find it.
Sorry, I kind of rambled on, but I wanted to make sure I got as much detail in as possible.
Anybody have any ideas?
