Help!! lost gas milage

[BLACK&chrome]

hey guys, new here but have been patrolling for about a week. I recently bought a 99 ccsb 2500 with a 5.7 4x4. was getting roughtly 13-14 mpg. Well the other day I got stranded at the car wash. im thinking the bendix spring is weak as I haven't had a problem since but ive also haven't tried restarting it while it was warm again. while trying to start it would catch just enough for it to build pressure then kick out. Possibly causing extreme back pressure as I could hear the motor "snort". well since then ive went like 30 mile in town and used 1/2 a tank in gas about 5-6 mpg... WTH!! does anyone have a guess to why this is?

After I get this problem sorted I would like to start updating the engine to optimize hp and mgp just get a fine balance. yes I know light foot blah blah.. we are all grown ups and know better so no need to say that. but its been like 13 years since ive owned and up graded a 350 so ive missed a lot and would like to get your opinions on what I should do with it.

1. mpfi conversion
2. felpro gaskets
3. transgo shift kit
4 black bear tune
what else?

thanks in advance


also taking truck on a 400 mile trip tomorrow ill be scanning and trying to determine problem in the mean time.. maybe ill get lucky and if fixed itself hahaha

 

[BLACK&chrome]

Alright just did first warm start since the other day and it took a couple turns almost thought it wasn't going to start again. why is it doing that? on a cold start I barely turn the key and it fires up.

 

[IOWNJUNK]

Sounds like starter is headed out, the first thing when they start to go is they cant keep gear engaged in flywheel.

Have starter tested but dont forget battery and pos/neg wires from batt. If starter isnt getting full battery power it will not be efficient.

 

[BLACK&chrome]

well, the starter was changed by previous owner no more then a month ago... and 3 other times in the last month.. so that is another dilemma to decipher. but he kept getting reman starters so maybe just kept getting bad bendix springs or something idk.

 

[IOWNJUNK]

I had a Bronco II years ago, go ahead and laugh, I bought a starter for it at autozone that lasted 2 days, replaced it with a starter that didnt work at all. When I returned it that time I had them test the brand new starter and it cooked right there on the bench. It happens.

 

[BLACK&chrome]

ok I was wrong there was 5 starters in December alone. On 4/13/12 last owner replaced the distributer cap, rotor and plugs so I don't think that would have anything to do with it, possible but I don't think it is possible though. but aside from the basically non existent mpg and the warm start issue. The truck runs out good and idles smooth. any other suggestions?

 

[IOWNJUNK]

SES light on? Any codes?

 

[BLACK&chrome]

no light, no codes just scanned. one stored coded previously deleted was for bank 2 o2. other then that nothing.

 

[IOWNJUNK]

Are you sure its not just fuel gauge? Mine is far from accurate.

 

[BLACK&chrome]

Well just filled up n had just over 1/4 tank n it took 17 gallons so I Don't think its off or atleast not by much