95 5.7 Troubles

[dan6969]

Hey all!

I have a 95 yukon with 235xx miles and it has started to give me fits. It started with a little miss in overdrive and has progressed all the way through the power band. I have changed...... Plugs,wires,cap,rotor.coil.blackbox in dist. and IAC. Done the seafoam and BG products treatments. And then I took it to my local GM dealer and after 500.00 bucks of come here son and bend over... it still misses. I need some help. Motor is strong with good compression and always starts right up. It had a smoking prob but it was as easy as pulling the valve covers and cleaning the oil returns. I also have a 89 gmc with the 5.7 and never had problems like this. oh... It has over a half million miles on it and the motor is untouched(internals). I am stumped...any help would be great

[Genuinefine409]

Did you check the injector's and throttle body out? My brother had problems several years ago and was chasing ignition and here it was the one injector was bad. Somewhere in between 89 and 95 they did some reworking with the throttle body i think not 100% sure about that but i've seen somewhere 93-95 are different with something but if the injectors are the same try the ones in your other truck.

[skills4lou]

It's entirely possible that you need a new distributor. When the bushings get worn they tend to get sloppy on timing, and it's nothing that can be adusted. Some better shops can test the distributor for you if you take it out and bring it to them.

That's not to say this is for sure the problem, but it's a possible. Since you already replaced most of the other parts in the ignition this may be your fix.

This isn't a real cheap fix, but you'll want to spend a little extra for the better ones.

Of course, the injectors should be checked first because that's an easier thing to rule out.