Heres my problem I have 1997 chevy blazer with a w code 4.3 it sputters at 1500 to 2500 rpm I've replaced fuel pump fuel filter plugs wires cap rotor tps maf all acdelco I'm at my and with it the only thing I haven't done is replace my cat I've had my laptop hooked to it so i could read the codes but they're were none the gas mixture is alittle lean its like 40 to 60 and that's at running temp 210 degrees but I don't think that will cause it to spit sputter so I'm hoping you guys will help me thanks

 

Geez! I'm surprised you didnt throw a Distributor and Ignition module at it, too.

What does your MAP read out at idle?

Does it also do this cold? Or just once it gets to temp

 

It does it when its cold too an the map reads normal

 

What's normal?
Does it do that at that rpm all the time, or just under load?
Run the KOEO fuel pressure and leakdown test if you havent. You need 60 lbs psi

 

I been working on cars for 10 yrs I hate when things don't run right so I started replacing things that I would think it would cause the problem and I know acdelco runs best in these engines

 

Look.. I've been working on cars 50 years and on EFI for over 20. All in Driveway but I know Probst pretty much forward and backward.
Frankly I tend to do the same as you did. It's beyond that, isnt it?
I'd be glad to help but first we have to establish performance baselines and you might have to supply answers you think are settled.

One of the questions was what MAP read at warm idle.
And need to know if it's rpm or load@rpm related

And another weird request is when you get car warm, shut it off, disconnect MAF and drive it.

Otherwise, some other things to look at. Pull and clean the EGR. Take off dist cap and look for signs of abnormal wear/scraping from rotor; wiggle and twist rotor checking for side slop / gear wear

Does the normal ECT temp {on scan} run 210 at idle & cruise? That is a TAD high. Should be 195-200

 

I just checked the map sensor again and it is not reading right I let u all know tomorrow when put the new one on

 

Sorry I didn't mean to hurt any feelings I'm just frustrated I'm try explain to my best of knowledge

 

Ill try clean the egr tomorrow and the 210 temp is at idle cruising temp is between 195-200

 

I'm in my barn right now so I just check for gear slop in distributor and there is no slop and I'm sorry forgot it only does it under load