Low Idle While In Gear

[rob-2]

The problem that first appeared on my low compression motor appears to have reappeared on this rebuild.

 

7K miles ago I had a block re-done with forged pistons. Broke it in properly and started driving it. On the first long oil change I consumed 1qt in 2500 miles. Shop said it was a little more then expected but within the norm. The last one they built consumed 1qt in 3500 miles and they expected between 3.5-4.5k 1qt consumption.

 

This level remained consistent for the next oil change. However what has developed is a dip in the revs while stopped in gear and a near stall like feel sometimes while stopping. Most recently I received a slightly lumpy idle while in park.

 

Frequently while stopped the revs hit 1k while decelerating, hold about 700rpms and then slow drop while stopped. They keep dropping until the car is somewhat chuggin in gear, with the needle just about the 'stall' line on the RPMs. If I give it a bit of gas the revs come out and the cabin/wheel feel smooth oil.

 

It's going early Jan for an inspection and a compression test.

 

Questions:

1. Is oil consumption likely linked to this idle?

2. If compression is good what else might cause this idle problem?

3. Anything else to look out for?

 

On the first long oil change they inspected TMIC, downpipe and block for signs of oil. There were none.

[bigleben]

Have you check for any vaccum leaks?

[rob-2]

Have you check for any vaccum leaks?

 

Not specifically. Within the first few miles with the 16 psi tune I threw a few lean codes which were vac leaks. They told me they found them and the code hasn't returned.

[rob-2]

Well it's going into the shop next week to have a compression test and inspection done.

 

I'm getting a low idle which feels rough because I can feel each fire. More concerning I can random cabin shake while in N.