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95 5.7 miss. Please help.

pimpinNmyZtruck

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pimpinNmyZtruck New Member

pimpinNmyZtruck

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Hello all. First of all, I would like to thank you all for all of the wealth of information I have gathered from this site. The search button here has been an absolute blessing. Now to my problem...I have a 95 chevy 1/2 ton Z71 with a 5.7 and 4L60E...193.000 miles. It has developed the WORST miss. At idle it is fine. At WOT it is fine. But just cruising at 55mph with my foot barley in it, its like I am patting the gas. When revved up to around 1200 rpms and let off, it almost dies. I have changed plugs, wires, dist cap, rotor button, and fuel filter. I put a tps on about two years ago. I pulled the air filter and looked at the injectors and they looked to be spraying ok, even when I made it miss and sputter..... Also, and this may be completely unrelated, when it misses the worst the brakes screw up. The pedal pushes back then falls to nothing and I can hear air. I put a brake booster on it a year ago. I pulled the vacuum line off to check the valve and it smelled like a gallon of gas had been poured down it. The valve seemed fine though. It runs great and stops great when its cold. After I drive 10 mins or so all the problems start. Any help you be greatly appreciated. Thanks.

pimpinNmyZtruck New Member

pimpinNmyZtruck

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Well I talked to a mechanic buddy of mine and he said to try the map sensor first. I put that on today and it didnt make any difference. I guess Ill just have to run down the list and try one thing at a time. I dont mind working on things at all...but I HATE trouble shooting. It seems like its just throwing money at it until you find the right thing. Thanks for your help GMstrong. Looks like the ignition coil is next and Ill go from there.

92rado Enthusiast

92rado

Posted
Posted

It sounds to me like your getting to much fuel and it's loading up and causing it to pulse. I would the temp sensor first or oxygen sensor. Both are pretty cheap.

mathewsmatt Enthusiast

mathewsmatt

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I had somewhat of a similar problem with my 94 chevy Z71, same motor and tranny as yours. mine would idle fine, but once you put a load on it, it would act like it wasnt getting enough gas to it, but then youd let it sit, then crank it up and it would run great for 2 minutes then do it again. we tried everything and it ended up being the sock/filter screen on the bottom of my fuel pump/sending units pick up tube, it was ripped open and folding together so when the pump would pump more fuel it wouldnt get the fuel it needed to get. so we replaced that and then it ran as good as new.

that may not be your problem but its something u can check.

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