LS1FIRE

iTrader: (1)

Hello yall, i been doing some logs with hp tuners, as soon as i start my car in the morning everting runs good, but when im on my way home the Map sensor Flat lines to 10kpa and I get the P0107 code, then the next morning the map runs fine , then when I get to my parking lot, p0107 and the map flat lines to 10 kpa, also i get the p0449 evap sensor code somtimes. What could be the problem?

Russ K

iTrader: (1)

Check the reference voltage to the map, key on engine off should be 4-5 volts, if not check for an open/grounded reference circuit. I had the same code on a 1999 5.3 truck and it turned out to be a faulty pcm.

Russ Kemp