Hi I have a 91 s10 blazer with a 4.3L engine non vortec. When I press the gas to go. the throttle response is sometimes slow and other times reacts quickly. I was wondering if anyone knew what this could be. It idles fine. just poor throttle response.

I have replaced

Cap and rotor
Spark plugs- Bosch ( should I get acdelco?)
02 sensor
fuel lines that were leaking
oil changed 200 miles ago
put lucas transmission fix in my tranny
used lucas deep clean for cleaning fuel system
dropped the tank to put in new fuel sending unit cleaned out gas tank too

I think i need new battery too. what would be recommended.

Thank YOU :]

 

Get rid of the bosch plugs! these things hate em! put in ac delco coppers or ngk v powers(go with the v powers,my 91 loves em!)

 

Im going to get the v- powers right now then thank you :]

 

no problem! Also,clean out your throttle body. take off the air filter housing etc. open the valves in the throttle body and spray some carb cleaner in there on the walls and "butterflies" and scrub it with a toothbrush etc.



edit.

Oh if you have a oreillys around there. get the plugs from them....they are 2 bucks each there..or at least all around my area..anywhere else is $3-$4 each. you can always get em to price match too!

 

Yea I price checked the at advanced auto and they were 2 and auto zone wanted 2.50 so i went to advanced auto and got em. :]. Also got a new battery for the blazer the other one was bad.

 

Cool. put em in and let us know how it runs then. Also when you replaced the cap&rotor,you sure you didnt turn the distributor etc? your timing might be off causing it to run strange.

 

My blazer still isnt running right. When its cold the throttle is firm. then when it warms up the throttle reponse is weak and it dosent want to go.

 

Starting to sound like a fuel issue. You need to have the fuel pressure checked once its warmed up and driving bad. has to be 10-13 psi. You said you replaced the sending unit. Did you change the pump too? If it is a pump issue..Only buy an ac delco brand pump. These do not like anything else. Dont cheap out like i have and many others. you will be back in it within days to weeks. The pump can be found on rock auto for 40 bucks. Same cost as the cheap pumps.

Before doing all that if i was you id open the regulator and drop a quarter under the spring. It'll bump the pressure 1-2lb. See if that helps.

Also,did you replace the fuel filter?