Fuel Feed Problem???

[jgimar]

i have a 92 gmc sonoma with 4.3 v6 throttle body fuel injection. it's an old beater but it runs relatively well most of the time, until recently. about 3 years ago she quit on me and i replaced the fuel pump. problem fixed. about 2 years ago it quit like before. i replaced the fuel pump again only this turned out not to be the problem. once i got it to a mechanic, i was told that a fuel injector had gone bad. 300 bucks later everything seemed to be fine, until last summer, a real hot one here, it wants to buck and sputter after it's run for awhile. i have good fuel pressure, new fuel filter, tuned it up with plugs, wires, cap, and rotor. this was last fall right before i took a long trip with it and it seemed to subside, but the heat wave had subsided so i may not have got a good feedback. anyway, ran alright since, until now and the high heat is back and it's started bucking again. it seems to run fine at high speed but when you drop back to about 30mph, or let it sit a bit and crank it up to go again, it gives you that act like it's out of gas, or not getting any.
can anyone point me in the right direction on what to look for or replace?

 

[Molson02536]

i have a 92 gmc sonoma with 4.3 v6 throttle body fuel injection. it's an old beater but it runs relatively well most of the time, until recently. about 3 years ago she quit on me and i replaced the fuel pump. problem fixed. about 2 years ago it quit like before. i replaced the fuel pump again only this turned out not to be the problem. once i got it to a mechanic, i was told that a fuel injector had gone bad. 300 bucks later everything seemed to be fine, until last summer, a real hot one here, it wants to buck and sputter after it's run for awhile. i have good fuel pressure, new fuel filter, tuned it up with plugs, wires, cap, and rotor. this was last fall right before i took a long trip with it and it seemed to subside, but the heat wave had subsided so i may not have got a good feedback. anyway, ran alright since, until now and the high heat is back and it's started bucking again. it seems to run fine at high speed but when you drop back to about 30mph, or let it sit a bit and crank it up to go again, it gives you that act like it's out of gas, or not getting any.
can anyone point me in the right direction on what to look for or replace?

Try cleaning the EGR valve and replacing the MAP sensor, It would not hurt also to give it a http://www.seafoamsales.com/ treatment which will clean out most of the carbon build up in your engine.

Other area's to inspect and replace are the Vacuum hoses if they are dry rotted and cracked from the heat and time.

Start with these few things and keep us posted

Molson02536

 

[happy 2011]

Try cleaning the EGR valve and replacing the MAP sensor, It would not hurt also to give it a http://www.seafoamsales.com/ treatment which will clean out most of the carbon build up in your engine.

Other area's to inspect and replace are the Vacuum hoses if they are dry rotted and cracked from the heat and time.

Start with these few things and keep us posted

Molson02536

why tell him to replace parts that you do not know are bad? Are you one of those parts changers that buys parts till it's fixed? Hope not becaues it cost more to do that!!

 

[Molson02536]

why tell him to replace parts that you do not know are bad? Are you one of those parts changers that buys parts till it's fixed? Hope not becaues it cost more to do that!!

Something called preventive maintenance, guess your one of these guys who drive around till you have a tire blow out after the steel belts wear through your tires happy.

If your can make your car still run like a champ after 410,000 miles with the original drive train without maintenance. Please do share to us all cause i would like to know how to go past more then 2 years for new u joints and ball joints and tires ect happy.

Thank you for more of your negative inputs and i guess the EGR valve and MAP sensor will still be working conditions after 20 years of service in the the engine. Wish i had a Typhoon that could go that long without running up bills or maintenance like what magical truck you drive.

Molson02536
1992 Typhoon.
1996 Jimmy
1996 Blazer
2002 2 dr jimmy (http://www.wynjammer.com/)
2002 nissan frontier
2003 montana
2003 pt cruiser gt
2007 Prevost

 

[jgimar]

i appreciate the suggestions and I WILL change out those parts suggested. this thing has almost 200 grand on it and i don't believe any of those have been replaced. i'll see what happens.

 

[jgimar]

at least someone provided me with some ideas. thanks molson.

 

[happy 2011]

listen molson
I do this for a living... You know a pro!
All you ever do is tell people to replace parts with out checking to see if they really need them. This is why i give you neg feed back.
You want to help people tell them how to test the parts instead of replacing them to see if it helps. That is of course if you know how to test them.

There are too many people out there (you) telling people to just throw money at it with no diag to see if they really need the parts. I diag every thing i replace and NEVER guess or tell anyone on here to guess and just replace it and see if it helps!

Now i won't help everyone on here becaues some people just want a quiock fix! I will only help people that will help them selfs. People that to me seem like there really trying. Then i will talk to them or pm them.

You just jump in all the threads and start telling them to replace this or try that and in the end you just cost them money they should not spend!

 

[jgimar]

ok so happy 2000, help me out here. how do i check to see if either of these parts are faulty? or do you have any other advise on what i might look for?

 

[happy 2011]

well i tell ya this don't replace the map sensor becaues at highway speed or 30 mph the engine vacuum will be the same at steady thottle.

Egr valve sticking would cause it to stall at idle..

Now i belive you only have 1 o2 sensor ? Unplug it and drive it and see what happens and see if there is any diffence.

Also tell me about what brand of cap, rotor and wires you put on?

Also is it a auto ar standard tranny?

 

[jgimar]

thanks for the help. just got around to checking this so it will be a couple of days on some of this. i'll have to see what i can tell you about the parts. it's been a year and of course i don't have any boxes. i do remember that i bought them at NAPA. and the thing was doing the bucking before i changed them out. the O2 sensor i haven't touched. if i remember right, it's underneath on the exhaust pipe coming out of the manifold, right? i just drove over to medicine lodge yesterday. about a 90 mile trip or so. air temp here is pushing 100. all the way down it ran just fine. once i got there i let it set for a couple of hours. on return home i got about 6 miles out and it started buckin'. acts like its not getting fuel but it does it for a bit then smoothes out again, runs ok for a bit then starts to act up again. when you come to a stop it drops down to idle speed, does alright for a bit then really drops off and dies. you can crank it righ up again and get going but it's just annoying. tranny seems to be doing fine. thing has almost 200 grand on it. last fall. fuel pump is going on 2 years old. plugs, wires, rotor, and cap are less than a year old. also it's an automatic.
appreciate the help.

 

[jgimar]

oops my bad....it's an automatic.

 

[jgimar]

happy 2011. well i've located the O2 sensor but unplugging it may be a real chore. the plug has been secured to the transmission dipstick tube and it's in a location that i can't get to. and even if i was able to unplug it, i doubt i would ever be able to reconnect it without tearing half the undercarriage out.
any suggestions.

 

[jgimar]

happy 2011. well i've located the O2 sensor but unplugging it may be a real chore. the plug has been secured to the transmission dipstick tube and it's in a location that i can't get to. and even if i was able to unplug it, i doubt i would ever be able to reconnect it without tearing half the undercarriage out.
any suggestions.

 

[jgimar]

well i tell ya this don't replace the map sensor becaues at highway speed or 30 mph the engine vacuum will be the same at steady thottle.

Egr valve sticking would cause it to stall at idle..

Now i belive you only have 1 o2 sensor ? Unplug it and drive it and see what happens and see if there is any diffence.

Also tell me about what brand of cap, rotor and wires you put on?

Also is it a auto ar standard tranny?

well i found the O2 sensor, but i'll be damned if i can unplug it without tearing twenty other things off. i can see where it runs up into the engine compartment. is the a plug up there that will be easier to get to?