Bought my first T/A about 1 month ago. It was running excellent until the other day, it seems to want to search for an idle and the gas mileage doesn't seem as good. When I put the A/C on it wants to die and the engine is trying to compensate for it you can hear the air volume being sucked in harder through the filter. This is what I did today.

1. checked AFPR for proper pressure set at 48 lbs
2. Scanned for bad codes none present.
3. Also when I take it through the gears it has great pick up and power but it sounds and feels like it is tugging a bit? Almost like a backfiring sound but not loud and it goes away with more throttle acceleration.

The following are my engine specs:

Older 350 bored .060 over to 358 C.I.
DECK BLOCK-- .010
Resized rods w/ ARP bolts
Crank Machined .010 rods/ .020 Mains
Heads decked .010
3 angle valve job
Isky cam and lifters 264 degrees/264 @.050 214/214
intake lift 450/exhaust 450
10:1 compression
slp runners
SVO 24 ILB injectors
1.6 rollertip rocker arms
LT-1 Valve springs
edlebrock tubular headers
Big Mouth manifold
3" high flow cat
Flow master exhaust
world class T-5
high volume oil pump
double roller timing set
52 mm throttle body
H.E.I. Ignition
custom prom

The motor has about 8000 miles on it and all emissions are intact and working.

 

In your list you posted "custom prom". Is that something you burned yourself, an off the shelf chip, an actual dyno tune, or someone's best guess? What are your BLM's at running at idle?

 

The custom prom was sent out and burned based on the engine specs and it was running great. I will post all the monitoring results with the diagnostic tool hooked up before it warms up and after it is warmed up over the weekend.

 

BLM AT IDLE = 108