Poor gas Mileage on 350 Vortec and a Miss Still

[1997chevydriver]

Well ya, but the op too. Empty really isnt empty if ya know what I mean. Mine will be at E an its all I can do to get 24 gals in it

How can you guys run your tanks so low? I dont let mine go under a 1/4

 

[JAW's]

How can you guys run your tanks so low? I dont let mine go under a 1/4

I usually don't either but one day I was running late and found out that an 3/16 on my tank is empty ... now I dont let it get much below half

 

[am92]

Well ya, but the op too. Empty really isnt empty if ya know what I mean. Mine will be at E an its all I can do to get 24 gals in it

Yeah, i know...the very lowest mine has ever gotten was about 24.5 when I filled up and I was freeaking out thinking I was gonna run out. I guess they build in a safety factor when they set the guages

 

[bluex]

How can you guys run your tanks so low? I dont let mine go under a 1/4

just keep driving man. Every GM that I have had that's newer than 95 has always had 4 gals left in the tank when its on E...

 

[1997chevydriver]

just keep driving man. Every GM that I have had that's newer than 95 has always had 4 gals left in the tank when its on E...

I dont do it because of running out....

I do it for fuel pump life

 

[davbell22602]

Sorry to be the bearer of bad news, but 330 miles to the tank sounds about right for one of these trucks. Right now I get about 11-12 mpg city/ 15 hwy ... As for the miss, you said it isn't throwing any codes? One of the only things you haven't replaced is the distributor itself. I've heard that the gear can get worn though and that will throw off the ignition timing causing a miss. You can pull it and check to see if the gear has knife-like edges to tell if its worn out

I thought these 350 vortec was supposed have better mpg than the throttle body. I know guys with the throttle body and there getting around 20 mpg. I dont have a dizzy wrench to check it.

 

[davbell22602]

How many gals are you putting in it when you fill up?

I usually go between 350-375 miles on 23-24 gals....

I dont know how many gallons I oput back in but the most miles I can drive on a full tank is 315. When my reads its empty when the needle is on the last half of the last empty mark on the gauge.

 

[TruckinAin4Sissies]

I thought these 350 vortec was supposed have better mpg than the throttle body. I know guys with the throttle body and there getting around 20 mpg.

I dont have a dizzy wrench to check it.

AutoZone, next to the left handed Allen wrenches.

Pull the cap and check the points on the underside of the cap.
Also check the 2 vent holes on the distributor, make sure they're clear.

If you DO pull the distributor (to check the drive gear) be sure you drop it back at the same exact spot.
Better yet-- afterwards get it scanned to check the CAM OFFSET. It should be at 0 +/- a few degrees.





-Truckin'-

 

[davbell22602]

AutoZone, next to the left handed Allen wrenches.

Pull the cap and check the points on the underside of the cap.
Also check the 2 vent holes on the distributor, make sure they're clear.

If you DO pull the distributor (to check the drive gear) be sure you drop it back at the same exact spot.
Better yet-- afterwards get it scanned to check the CAM OFFSET. It should be at 0 +/- a few degrees.





-Truckin'-

If have to get it scanned then I'll probably pay someone to just fix then. I dont have access to a scantool. The shops around charge $100 or more just hook up a scantool.

I see your confused on my throttlebody statement. I mean the early throttle body that was used in the early gmt400 trucks 88-95.

 

[TruckinAin4Sissies]

If have to get it scanned then I'll probably pay someone to just fix then. I dont have access to a scantool. The shops around charge $100 or more just hook up a scantool.

I see your confused on my throttlebody statement. I mean the early throttle body that was used in the early gmt400 trucks 88-95.

Ah, ok. TBI




-Truckin'-