Thread: Poor Performance and RPM climb following LIM install

Hi All,
I'm looking for suggestions to fix my '99 GTP from the following conditions...
I just replaced the LIM along with, valve cover gaskets, plugs and wires. Other than running it around the neighorhood the get up to temperature and check for leaks, this mornings trip to work (40 miles) was the first real test. She ran like a champ for the first 30 miles, but after a slight increase in speed to change lanes the boost gauge on the info center showed about 1/3. At that point I did not notice a change in performance. within a couple of miles the boost indicator moved up to 2/3 and I noticed a hesitation and lack of throttle response. For the next 8 miles the rpms climed to almost 4k, the average mpg went from 32.8 to 16 and it really stumbled upon stops. I limped to work and checked for leaks - nothing obvious.

I think I hear a vacuum leak somewhere, but it's hard to tell with the K&N intake noise at the elevated rpms. This LIM was the most aggresive repair I've ever attempted, but the oil smoke/smell had me convinced that my car would be a charcoal briquette if it was not fixed. The only difficulte I had (or think I had) was the routing of all the wires upon reassembly.

There are no dummy lights on and the temperature fine throught the trip this morning.


Any help would be appreciated. I'm not looking forward to the trip home tonight.

Thank you,
Joe

Just ran out during lunch and found a vacuum line that was not attached. It was part of the line that came from the front of the S/C, "T"ed off into the LIM under the snout and went around to the back of the S/C. The problem is I don't see a place to seat it.
Does anyone know want this vacuum line terminates to on the backside of the S/C?
Thanks again,
Joe

Found it.


I found the attachment pont - bottom side of the MAP sensor. She idles fine now, run up the street with full power again and hopefully the trip home will be uneventful.

Thanks to slick2500 and all the contributors on this site.
Joe