Car has been running fine for awhile after extensive repairs. Took it out today and out of no where it just started running horribly. In the past i had a couple spark plug wires sit on the exhaust manifold and burn up so i had a couple dead cylinders. which was noticable right away of course. at one point it had hit 4 out of 8 of them and the car was running on only 4 cylinders. (only for a couple hundred feet at most). well today it started doing the same thing(at least it felt that way) I immediatly thought that maybe one of the wires had moved out of place and shorting out. Nope, I have now replaced all spark plugs and wires, The distributor cap and rotor, fuel pump relay, and 02 sensor. Not a single thing has changed. This morning when i went to the store it ran perfectly fine, 2 hours later when i went to leave again all this started happening. Im am completely lost on this, I have checked everything that i can think of and nothing is happening. It sounds like it is sputtering really bad ( like it would sound if there were dead cylinders) i stomped on the gas peddle and watched a lawnmower pass me up. The dizzy replaced a few months ago, the ignition coil appears to be fine. It is a 5.0 tbi and both injectors appear to be running fine, one looks like it might be vibrating a lil more than the other but that could be because im paranoid. engine was completely rebuilt about 5k miles ago. Any ideas on what it is that is causing this nightmare? Thanks in advance for any and all help.

 

I know you mentioned the injectors look like they are working but I would check to make sure thet are. I say this because I had a 91 S-10 V6 with a throttle body and it started acting like you would cut the power in half. Wouldn't get out of its own way etc. Found a connection was loose at the computer that powered one of the injectors. Fixed that and it ran fine ever since.

 

I'm haveing the same problem, it sounds like its stalling to me, like somethings going wrong, and i replaced my fuel pump like 4 days ago, and it started sysophning gas out of the vent line, i had to take off the cap to release the pressure, im not sure if thats the problem or not, i have the cap off now, and it just putters really hard, it almost sounds like a back fire, and if i floor it, it goes no where, it goes farther if i just give it a very little gas, but doesnt go more then 5 miles and hr, IF THAT, any advice would make me happy

 

I have rebuilt the top end of the motor and replaced aLL the gaskets all the sensors fuel pump, fuel filter, fly wheel, starter, battery, altinator, just about everything.. I'm so stumped how to fix the syphoning problem, and i also have one vacuum line just dangleing i have no idea where it goes too, its the one from the firewall, the shorter one on the passenger side, it has a 90 degree fitting, if u could tell me where that goes, that would also be apprechated.. If i find a fix i'll be sure to fill u in

 

Oh and its a new transmission, for awhile it was shifting into all the gears fine, i could go around the neighborhood twice, no problem now all the sudden its giveing me a hard time doing this, i can get it out of the garage, up my cudisac, and maybe a 100 feet away and it just starts to stall and putter, and goes absolutly no where...