highperf86

I have a 1990 s-10 4.3 5speed, runs great for about 2 minutes after start up, then when i try to accelerate it starts bucking and misfireing and boging. im at aloss please help, ive changed almost every possible sensor still no help. getting engine code43,33. any help will be greatly appreciated
thanks, chris

TopDogg

Code 33 is a map sensor problem. Check the engine for vacuum leaks. Check the exhaust for blockage (catalytic converter). The map sensor may be faulty.

Code 43 should be electronic spark control. Your ESC module or your knock sensor is defective.

How long have these codes been up before problem began? How does it run in park (nuetral) while reving engine?

highperf86

the truck runs fine in nuetral. the esc code came on after i replaced the map sensor, i dont know if the computers feeding me crap or what?
could it be the coil? or maybe the esc module? i cant find the knock sensor. the idle air controll sensor is making it rev up then down so i disconnected it, it idles the same rev now. thanks, chris

91red

Change the ignition wires. It sounde like you have one breaking down when under load

highperf86

are they the plug wires? if not where are they?

91red

Yes they are the same as plug wites. Sometimes they can get weak and the motor will idle just fine but will breakdown under load. Not a bad idea to change the sparkplugs at the same time.

highperf86

i did that, it still misses really bad?

TopDogg

You got a code 43 for a reason. Check ESC. Even check small things like is distributor cap seated correctly? Free from cracks? They are cheap so change cap and rotor. Could just be a poor connection. Try starting up at night when it is dark, lift the hood and have someone put it in gear and give it a little gas (while other foot is on brake). See if you see any spark jumping anywhere around coil, cap or plugs. You say it runs fine in nuetral so do it in gear.

quiktsi

Check your distributer cap and your coil to make sure you are getting the correct spark.