Anyone familiar with the 4.3 in the '98-up S-10/Sonoma?

["Turbo-T"]

Might be getting a 99 Sonoma with a rebuilt 4.3 liter. The truck surges when you give it anymore than 1/4 throttle. It's like on Beverly Hills Cop I where Axel puts the bananas in the tail pipe of the LTD II that the 2 undercover cops were driving. The truck goes forward, hesitates bad, goes forward, hesitates bad....under 1/4 pedal it's fine. SES light is on, no codes checked yet.

I'm thinking maybe a bad MAF? Could it be a bad O2 sensor? What else could cause this?

 

[TR Custom Parts]

Got two of them! Check the codes, that's what they are there for. Could be bad MAF, clogged cat??

 

[Steve V]

I agree check the maf,unplug it and go for a ride.

 

[Quick6'n'-K.C.]

Does that truck have the octopus fuel system under the intake?

I would put a fuel pressure gauge on it, bet its the fuel pump.

Guy at work has had 2 of those, and friends dads have had those trucks, the fuel pump causes all sorts of issues with those trucks
BW

 

["Turbo-T"]

Not sure about the octopus fuel intake you're referring to. It's a CSFI engine if that helps any. The farmer selling it has no idea why the SES light is on.

 

[TR Custom Parts]

Bad injectors on these usually will cause a bad idle, replaced both of the units on our trucks, don't think it is that problem with yours. Instead of the fuel pump could also be a clogged fuel filter.

Had a weird thing happen to my 96 Blazer today. Did an oil change with filter. No biggie right? Start the truck up and was covering the whole street with a nice blue smokescreen coming out the tailpipe. Truck was running fine before.

Had the truck up on ramps and put in 5 qts of oil and that was it. Only thing I can think of was having the truck up on ramps and the oil backed up in the head and got down a valve guide????? Eventually cleared up. Truck has 165K miles and hasn't been opened up except for the fuel injector change.

 

["Turbo-T"]

Well the seller called me this morning, and told me there's a temp sensor that dictates how much fuel goes in....not sure if i understand this....maybe someone here does?

 

[Steve V]

Coolant temps sensor,it is a thermistor. As coolant temp goes up the resitance changes and the ECM see this and pulls fuel. If it goes bad it can cause the ECM to think the engine is cold and dump too much fuel. It should set a code.

 

["Turbo-T"]

Hey Steve. That sounds about like what he was saying. All I know is if you gave it too much gas pedal it would hesitate bad.....no power....it was dark so i didn't see if it was belching up a bunch of smoke or not.

 

[Quick6'n'-K.C.]

I just bought this for the guy at work tonight. These sell for 234.00 normally.

Guess what broke today at work... You jinxed it

eBay Motors: NEW FUEL PUMP 1996 BLAZER & JIMMY 4 DOOR MU13 E3925M (item 120373823288 end time Mar-06-09 14:56:03 PST)