Mechanics

94 S-10 BLAZER

1994 Chevrolet Trailblazer

I have a 94 s-10 blazer with a 4.3 Vortec engine that when the engine heats up you have a type of a miss in the engine. Have changed all plugs, wires, cap, and rotor, and coil. Still have same problem especially when you put on the brakes. It tries to die and jumps like a straight drive when you don't mash the clutch in when coming to a stop.
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Momoandrick
August 13, 2006.




With no engine codes it is going to be a little hard to figure out. When this happens, if you place the truck in neutral and rev the engine, does it run smoothly? I would put me a direct reading fuel gauge inline of the fuel system and see if it is loosing fuel when this happens. With the ignition and fuel completly computer controlled, it is either seeing a bad indication from a map sensor, or MAF sensor and adjusting the mixture wrongly. This should be caught by a code. If the crank or cam sensor is sending a bad signal it can mess with the injector operation or ignition.
Have you checked you plugs for fouling? Some of the Chevy had hard plastic tubing running the fuel in the intake, and when those got old they cracked allowing fuel to run into the intake. Maybe it is collecting as the engine warms up and then running rich. When you brake it might run into the cylinders. Just guessing here.

Tiny
Mikeybdman
Aug 13, 2006.
With no engine codes it is going to be a little hard to figure out. When this happens, if you place the truck in neutral and rev the engine, does it run smoothly? I would put me a direct reading fuel gauge inline of the fuel system and see if it is loosing fuel when this happens. With the ignition and fuel completly computer controlled, it is either seeing a bad indication from a map sensor, or MAF sensor and adjusting the mixture wrongly. This should be caught by a code. If the crank or cam sensor is sending a bad signal it can mess with the injector operation or ignition.
Have you checked you plugs for fouling? Some of the Chevy had hard plastic tubing running the fuel in the intake, and when those got old they cracked allowing fuel to run into the intake. Maybe it is collecting as the engine warms up and then running rich. When you brake it might run into the cylinders. Just guessing here.[/Quote: e04c8eb722]

We have used a hand held computer/scanner and it read no problems found. Could this possibly be the torque converter? And is the transmission electronic. It does have a push button 4 wheel drive.

Tiny
Momoandrick
Aug 13, 2006.
Hey what Mikeybdman was saying may be what is wrong with your truck.I have a 1993 S-10 Blazer vortec 4.3 and my truck was running rough. When I would stop it would buck and rattle and the idle would drop almost to the point of stalling. Have you noticed a big loss in fuel mileage or black smoke and carbon coming from the exhaust?I pulled my upper intake plenum off and switch the key on and noticed fuel pouring out of a crack in the incoming plastic fuel line filling up the intake. My truck would run fine as long as I was driving but when I stop it ran awful. Instaed of paying $100 for new lines I bought rubber fuel line for under $5.00 and replaced both lines. Now the truck runs like new again. It is a very common problem with these motors. It also may be a leak in the " spider assembly" which consists of the fuel pressure regulator and six plastic fuel lines going to the injectors. Only way to know is to pull the upper intake plenum, and see if it is leaking. Hope this helps and if this isn't it email me and I will try to help you out.

Tiny
Paulb
Aug 14, 2006.
Thanks to everyone for the help. My Dad figured out what was wrong with it today. Thank God! It was the EGR valve it cost 165.00, but is running great.
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Tiny
Momoandrick
Aug 14, 2006.

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