It run perfect when you first start it but when it get warmed up, when you press the gas it act like it running out off gas then it will just take off like you smashed the gas and it run bad at a constent speed. and when you slowdown at a stop it starts missing. It has a brad new fuel pump, fuel filter, plug wire are brand new, spark plug are maybe 4 month old. I thought it was a vacuum leak cause my egr lost a nut i fixed that and it still doing the same thing but not as bad..sorry it a long just want to say what its doing. any help would be greatly appreciated.

 

i had a 93 3.4 engine that did the same thing to me but i ended up selling it. i did pretty much everything wat u did i changed all the things that could have been the problem.i would check the vacuum hoses to make sure cuz that could be the problem

 

Here are two possibilities. One - sounds kind of like your fuel pump may be cutting out. Get your fuel pressure checked to make sure the pump is good. You could have just got unlucky with you new pump. Two - I had a problem about 2 years ago with an electronic temperature sensor. It was telling my engine that it was running extremely hot when in reality the engine was running just fine. This caused the engine to cut fuel and it would make the car chug and spit. It did this more at constant highway speeds than anything else. I got this one figured out through a scan.

I hope one of these tips helps you out. More likely it will be #2 though.

 

Check your O2's

 

The pump def good i checked that out right away, if it was the sensor it should throw a DTC code, i had it happen but oppsite cause my sensor said it was cold and not kicking on my fans, i replaced my left O2 ill check my other one tonight.

 

I made this same mistake.... Always replace your o2's in pairs.
If you need another one save yourself some money and buy this one. https://www.camaroz28.com/forums/sho...d.php?t=714030