Ok to start off with been reading these forums for awhile now but this is my first post ive always been able to figure out my problems in the past using search and doing some reading. Now on to my problem(s)

I have a 1994 S-10 blazer 4 door, 4 wheel drive 4.3L CFI (vin code W)
Only getting about 7 mpg and it surges when driving at a steady speed and is running rich. So far I have replaced the fuel pump (it totally quit), fuel filter, removed and cleaned the EGR as stated elsewhere on these forums, replaced the oxygen sensor, spark plugs (AC delco), wires, distributor cap and rotor button. The check engine light comes on if I am driving 55mph or more for more than 5 minutes (codes 45 and 51). Before it's asked no I haven't done a fuel pressure test yet (just got back from hitting all 6 parts stores in my town none of them have a loaner/rental fuel pressure tester).
I really don't have much money to deal with seeing as how 5 kids + xmas in less than 3 weeks = a very broke me so I can't afford to keep guessing and hoping im right. I love these trucks (this is my third one) and this one looks almost brand new inside and out I really want to keep it but just can't afford to keep paying so much in gas every week (yes I know it will never be great on gas but this is horrid atm) Hope someone here can help.
Thanks in advance.

Oh one more thing, yes i cleared the codes after doing all the above work.

 

One thing to check might be the coolant temp sensor for the ecm. There are ways to test them I believe, but I'm not too sure. Does your temp gauge work? Maybe the thermostat is stuck open. Also might want to try a seafoam on it.

 

temp gauge works never seen it go higher than 200 and thats the one thing i forgot in my first post i did grab a can of sea foam while out lookin for fuel pressure tester and dumped that in my gas tank hopin that would help.

 

I would get another can and suck it in through the brake booster hose. Also you could have a plugged cat. I've read that those can cause major issues.

 

Disconnect your O2 sensors and see if that changes your mpg.

One other thing is vacuum, check all your vacuum lines.

 

well I dunno what happened but as I said last night put some sea foam in the gas tank but it was late so just drove home so today I go out and take it for a ride to burn up some fuel and get that sea foam through the system, anyways I come home shut it off and now it wont even rotate, turns about 1/8 inch then stops and returns to where it started from, tried removing the serpentine belt in case the power steering pump or some other stupid thing locked up but it just does the same thing. This thing only has 128,000 miles on it and oil is still full and no water in it, radiator is also still full.

 

Could be starter, or it could be a loose battery connection, or bad battery. Most autoparts stores wil check them for free, and can be checked while in the vehicel, or out. You just ahve to get them there.

 

yeah I thought about the starter too (it has once or twice just spun without engaging first thing in the morning) so omw out to clear a spot and beg my brother to come help me push it inside the garage /rude freezing rain and uphill sloped driveways atm will let you all know what I find out and thanks again for the replies, it is much appreciated.

Ryck

 

well starter and battery both tested no problems there, put em back on turned headlights on and hit the key, lights stay on (dim slightly of course) but otherwise same thing so any other ideas?

as always all help/advice greatly appreciated

Ryck

 

Ooooook me and a buddy just tried to turn the engine over by hand with 2 of us standing on the breaker bar (combined weight roughly 500 lbs.) it won't budge =/ so guess im looking for a decent boneyard replacement 4.3 vortec to get me back and forth to work while I rebuild this one. Oh man summit racing gonna looove me they havent seen me since I finished the oldsmobile toy.