Took my car out for a run, about an hour out, and another hour back. Everything is just fine until I'm about a mile from the garage. The car will not idle at all, it runs rough at low rpm's, gets a pronounced popping from the exhaust on coast-down, is hard starting, and has normal performance from 3,000 rpms and up.

It felt like a fouled set of plugs, except for the fact that it runs fine at higher rpms, but I changed the plugs anyway just to be safe. No improvement was noted.

For the record, I have a Pettit ECU upgrade, a PFS intercooler and intake, an HKS downpipe and Racing Beat cat-back. I live on Long Island (home of the US Open!), and I'm not sure about next steps.

The car seems to be running on the rich side (the old plugs were black upon removal).

Any thoughts, ideas, suggestions would be appreciated.

 

Sounds like your engine popped. Check the vacuum line on your map sensor.

Good luck