TOPIC: 1994 Chevrolet Silverado Ext Cab K1500 5.7L TBI

OK, third try. Apparently, I cannot type fast enough for the computer and my session times out but here goes again short 'n sweet!
My truck has 214,000 miles and last year I replaced a leaking intake manifold with the Edelbrock 3704 intake manifold. MPG's stayed the same 12-17. After talking to Ron, I fixed some vacuum leaks and had him Groove the TB. 20.1 mpg on the first run but that faded to 17 mpg avg. The last three test runs now avg. 18.9mpg. Computer has been reset and MAP sensor vacuum has been relocated at Ron's suggestion to the PCV port. Crankcase gases are now routed through an oil catch can to the breather extension.
More to come but computer session pushing me out.

OK, more info here. After installing the new intake manifold last year, I ran compression tests that resulted in 165 psi avg. on all cylinders with less than 5% deviation between cylinders. After clamping all vacuum lines this year and replacing a leaking EGR valve, static vacuum at idle was 20 in. measured at the MAP sensor. MPG's have gone from 12-17 before the Groove to 15-20 after with this work and replacing cap, coil, rotor, and wires with MSD Street Fire products. I think I should have better mpg by now, so I'm looking at these sensors, MAP and TP. They are 17 years old but not causing any codes. Any ideas?

Sorry for the delay, fellas, I've had some setbacks during testing last week but now I'm back on track with new results that are even better than before. I was testing on worn out tires (56,000 miles) when one had tread separation on a test run. A new set of tires will give totally new sets of mpg results so I had to start all over this past week. After logging a little over 200 miles, the average is now 18 mpg's which is much better than 12.8 for the entire year of 2010.
I will save some time by adding all the repairs in the weeks ahead and give you some results as they come in. As of now, the Groove results are minimal because of my worn out truck parts. More to come.

That's great news! From 12 to 18 is a 50% increase in mpg's!

Yee-HA!

Ron

Thanks, Ron. I could not have done it without your help and I have even better news! I've just got back from a road trip (took my son back to college). Before leaving I regapped the plugs from .044" to .050" (my truck spec is .035", 0' timing) and advanced timing to 12'. I had been getting good results at 12' & .044" but I wanted to see where the limits were. After 380 miles to college and back, the truck used 19.8 gal. for a new highway mileage best of 19.2 mpg. The highway mileage before was 17mpg. Today, I resumed testing after regapping to .044" and the results so far are improving. I'll let you know when the average hits 20 mpg.
I calculated a cost savings of $9.09 for the road trip.
The best is yet to come.