1993 k1500 4.3L spits & spudders during drive

vandanker · 03-03-2009, 12:24 PM

To All,
i recently ran it this problem with my truck.... truck will start fine and run great at idel. however when put truck in gear (5spd) and let off the clutch to take off i get no power just alot of spittin... if i floor the pedal then it will take right off. seems i have to be balls to the wall all the time in order to drive. no codes flashing so scanner will not pick up anything.. this is a list that i have already changed out.
iac valve
ignition coil
plugs wires cap rotor
map sensor
cleaned egr
and a few other sensors under the hood there are not many!! i think i have done them all.
i have even done the fuel pump and filter.

COULD IT BE THE ECM ITSELF??? WHAT ELSE IS LEFT TO DO ???
ANY HELP WILL BE GREAT THANKS

94 silverado · 03-03-2009, 04:02 PM

My 94 5.7 was doing much the same thing recently (also no codes). I tried everything I could think of too and finally took it to the chevy garage. They checked it out and finally decided to replace the EGR valve. It's been running great since then. Good luck!

vandanker · 03-03-2009, 06:34 PM

thanks for the idea, i have cleaned the egr valve, do u think i should just replace it.?

94 silverado · 03-04-2009, 08:34 PM

I think I'd give it a try assuming all hoses have been checked for vacuum leaks.
I know it's hard to spend for a part when you're not sure if it's going to fix the problem but it sure sounds like the same thing mine was doing.
How did you clean it? I would think there would be alot of possible carbon build up inside of it. Here's a link that may be worth checking out before you spend your hard earned money.
http://www.wisegeek.com/how-can-i-te...r-replaced.htm

vandanker · 03-05-2009, 05:25 AM

hi thanks for the idea, i have checked that that all the vacumehoses are good, i even replaced everone with this nice new yellow see thorough hose. i cleaned the egr with some carb clean i think. the plunger works amd it holds a vacume too. maybe i should try to replace it already i put like 250.00 into the truck what another 55 or so. lol not like i have the money to spend like this, but what choice do i have. thanks for that link i will try to replace the egr and i will let you know.... Thanks again ~Joe

smaurno · 03-05-2009, 07:20 PM

Did this start suddenly or has it been gradually getting worse?

vandanker · 03-06-2009, 12:11 AM

it has been gradually getting worse now that it has been a few weeks with out no fix, i've done everything i could think of on my own. now i noticed that at a idle the motor loops, like revs up slightly and drops over and over, maybe the fuel pressure regulator??? but i changed it about almost 2 years ago with a knock off brand could it go bad agian ???? any idea's thanks

ironhand33 · 03-09-2009, 04:41 PM

I too am having the exact same issue on my 88 k1500 4x4 5.7l.... Truck Idles fine adjusted the timing to tdc, and 4 deg. both ways still runs like crap.. Sometimes I can keep it idleing, put it in rev. or drive and it will die. I have no power and if I put my foot in it too much it will backfire. but will only backfire when in gear. I have replaced the: tps, map, egr, pcv, distributor, cap, ignition coil, rotor, plugs, wires, timing chain, both sprockets cam and crank, checked all hoses for leaks, replaced the injectors, the O2 sensor and have changed the intake gaskets. And am still having no luck...... I am bout to just drop an M80 in the gas tank and watch her burn.. Any Any Any suggestions would be appreciated...... I dont care if its probably the dumbest suggestion you have ever thought of, ie change the blinker fluid...

yeah shoot all of them at me....

smaurno · 03-09-2009, 05:25 PM

have you checked your fuel pressure? I was having a similar problem but less severe. Floor it, and it runs good. Otherwise, it runs bad. Changing the fuel pump stopped all of it.

ironhand33 · 03-09-2009, 05:38 PM

Quote:

Originally Posted by smaurno

have you checked your fuel pressure? I was having a similar problem but less severe. Floor it, and it runs good. Otherwise, it runs bad. Changing the fuel pump stopped all of it.

I havent checked the fuel pump yet. it just seems like its getting enough fuel cause when it idles I can romp it my throttle response seems a half a sec. slow then my idle kicks up fast. its when I put it in gear if i romp it, it spitts and spudders then wants to die.

smaurno · 03-09-2009, 05:52 PM

This is typical of an engine running too lean. When it's not under load, it will idle and rev fairly normally, but under load, it misfires and stalls. I'm not saying for sure that it's the fuel pump, but I would at least suspect it. The problem I ran into was that, initially, it was cheaper to change the part than buy whatever was needed to diagnose the problem. I changed the following before identifying the fuel pump as the problem:

EGR valve
EGR solenoid
coil
wires
spark plugs
cap and rotor
vacuum lines
fuel filter

The only reason I suspected ignition was that the problem got worse when it rained. By the time I was done, it would have been cheaper to buy whatever needed to diagnose the problem such as a fuel pressure gauge.

ironhand33 · 03-09-2009, 06:27 PM

I just came back in the house after taking my timing light and looking at the fuel spray from the injectors.. the passenger side injector has a circular spray when the accelerator is pressed and the drivers side has a mist still... could this be my problem? if so how would I go about fixing it? cause I had just replaced the injectors...

Ok just checked the spray again at different angles.. both are circular in spray... Im at a loss I dont know what else to do...

Quote:

Originally Posted by smaurno

This is typical of an engine running too lean. When it's not under load, it will idle and rev fairly normally, but under load, it misfires and stalls. I'm not saying for sure that it's the fuel pump, but I would at least suspect it. The problem I ran into was that, initially, it was cheaper to change the part than buy whatever was needed to diagnose the problem. I changed the following before identifying the fuel pump as the problem:

EGR valve
EGR solenoid
coil
wires
spark plugs
cap and rotor
vacuum lines
fuel filter

The only reason I suspected ignition was that the problem got worse when it rained. By the time I was done, it would have been cheaper to buy whatever needed to diagnose the problem such as a fuel pressure gauge.

did you change your map sensor your tps or your O2? cause Im getting all those codes.. I was told that I could be getting those codes due to the engine running lean, could this be correct? and could these codes be caused by a faulty fuel pump?

vandanker · 03-10-2009, 06:52 AM

hey been through all that, i have changed my fuel pump and filters, even the filters on the injectors themselves. for me next in line would have to be the pressure regulator. i changed it about 2 years ago, with some knock off brand but it is gonna keep me guessing until i replace it. i would try that next as i am too!!!

swingline · 03-11-2009, 12:52 AM

just pull the vacuum hose off the regulator and plug it
see if fuel comes out, if not drive it and see if it helps

vandanker · 03-11-2009, 05:52 AM

there are no vacume hoses.. there is a diaphram under the injector plate. i don't think there is a way to test

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