My 1999 blazer with 212,000 miles on it has always ran strong, I have put two fuel pumps in it, on the last one a fuel like cracked so i put that kit on it when you cut the hose and heat it up to slide a joint in the line to connect it to more line and that worked great. I have been having problems when i fill up sometime the fuel fills too much and runs out from on top of my tank, I am pretty sure the seal in between the tank and the pump is sitting fine. Also, while driving I have a spuddering feeling when driving and holding a steady gas. Almost like it does when your running out of gas but it does it consistently. If i go heavy into the gas pedal it takes off and runs fine.... I was thinking possibly and egr valve maybe? Any insight would be greatly appreciated.



Thank You~!

 

When was the last time the fuel filter was replaced?

 

You need to fix the leak in your tank. If you have not already, you will soon be getting an EVAP code because of it and this may cause you to fail an inspection.

As far as your puttering problem.. When was the last time that a tune up was performed? Have you tried cleaning the usual items (EGR, Throttle body, & MAF)?

 

I have that same sputtering problem with my s-10 blazer w/4.3L. I changed the fuel filter, checked the EGR valve and gave the truck a somewhat needed tune up and still have not figured out the problem. I'm begining to think it may be an emissions issue. An O2 sensor errror code keeps comming on but I change that also. I'm gonna watch this thread closely, if I figure this problem out I'll let you know. Good luck.

 

Yeah everything has been tuned up and the fuel filter got put in maybe 6 months ago when I put the fuel pump in. I do have an evap/02 sensor code when i run a scan on the computer. But low rpms it doesnt sputter much but around 2-3 grand it does the sputtering.

 

What were the specific codes?

 

I have the same problem with my 98 Blazer 4.3. Mine happens at low rpms under TCC lockup with steady pedal. It spudders then when I give it gas and unlock the tcc its fine. It also kinda hesitates for a half second when I floor it from a stop. I havent replaced anything yet but I have a similiar problem as you. I am going to clean my MAF and EGR. I will let you know if it helps my problem.

Oh and I also have a 02 code but it is sensor 3 which has nothing to do with fuel management right?

 

I can't quite remember the code number now but I think it was 13 (02 sensor). My blazer is a "second" vehicle that I don't drive much. Last time I drove it something went wrong with the tranny (gov. gear hopefully), so it's been a while sinse I replace that sensor. When I get the tranny fixed and it's back on the road I'll revisit the sputter issue. Hopefully, together we can figure this issue out.

 

Only the upstream sensors have anything to do with fuel delivery. For the 96+ B1S1 (driver side right after the exhaust manifold) & B2S1 (passenger side between the 'Y' in the y-pipe and the exhaust manifold) are the only two that have any impact on engine operation.

 

I will go get the codes ran again today and post what exactly they were.... Thanks for trying to help we need to get to the bottom of this ... Thanks again