My 94 blazer gets bad gas milage and also runs rough i put a new spider injector and the two fuel lines that plug into the spider and also a new fuel pressure regulator in it and a fuel filter still runs rough and gets bad gas milage i can smell strong gas odor sometimes but its not coming from uner the hood ? the motor only has 80k on it when it is fully warmed up it seems to have low oil pressure when ittling or in park when i push the throttle the oil pressure is normal ? could it be a cracked fuel line in the back ? or bad oil pump / oil sending unit i am about to give up on it
An expert who has achieved level 3 by getting 1000 points
An expert that got 10 achievements.
An expert that got 5 achievements.
An expert whose answer got voted for 100 times.
Re: really bad gas milage
The 93-94-95 all have this problem ..the fuel line that come into the back do split and leak ..other problem is with vaccum lines coming off the back of intake and vacuum lines come apart from a 3 way fitting.located fire wall .when these are off will cause gas smell and bad millage .... hopes this helps...
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
4.3 TBI (throttle body injector) You dont have a TBI you should be equipt with a CSFI people in the field call this the spider injector,they inject fuel into tubes for each cylinder , as for the fuel pressure it should be 54 psi to 60 psi,and this is for a 4.3, The CSFI system does plug up which causes rough idle due to the poppet valve or seat,to stick open or closed,Ive ran fuel injector cleaner that has been sucesfull maybe you can try that
If you replaced the injector after the plugsthey may be fuel fouled.Pull the plugs and clean them.(you can sandblast them,or use a method I used to use-shoot a little starting fluid on them and use a lighter to burn off the contamination of too much fuel).I can't believe GM kept using this stupid design so long-I remember nearly new Vortec V6s with this same problem in the '90s.
It could be a fuel problem, but in most cases the rough running would continue at road speed. You could certainly change the fuel filter and see what happens. A rough idle but no problems on the road would point to a vac problem or maybe a burnt valve. A fuel or ignition problem would be at most speeds including when you put the engine under a load. Its possible to have a faulty injector on one cylinder that is bad enough to cause a miss at idle but smooth out on the road, but that is a rare occurance.
You have a leaking injector assembly inside the intake manifold. These trucks had a very common problem with these. You'll need to buy the injector solenoid and tubes, it all comes as an assembly. The top half of the intake needs to be removed to replace it. I've attached a picture that shows the top half off and the injector tubes in question. Some people call this the injector spider as it kind of looks like one. The procedure is somewhat involved but if you google; "4.3 injectors spider repair" I'm sure you'll find many articles documenting it.
The vortec motor has been known for the so caller spider assembly which is the fuel injection set up inside the intake manifold going bad.The regulator starts leaking wich puts extra fuel into the motor.If that is it you should change the whole assembly.