84 302 power loss&backfire

[broncovilla]

I have an 84 full-size bronco with a 302. It starts and idles strong. When I give it gas it will bog-out, loss power and at times backfire. At first, I could shake the plug wires and the computer wires around a bit and it would work fine. Now, the loss of power is constant and immediate. So, I changed the plugs, plug wires and distributor cap. No change. Then, I cleaned the computer wire connectors. Still no change. My next step is to make an extensive check of vacuum lines but at this moment there appears to be no leak. I will also try a substitute computer module to see if mine is bad. If it is not the computer module or the vacuum lines, what would be my next troubleshooting step? Test for spark? Test for fire? Timing? Compression? Or could there be a carb problem? Fuel filter/pump problem?

 

[Seabronc]

Typically backfiring is caused by timing. When was the last time you checked it?

Good luck,

>-

 

[broncovilla]

Probably should do that...thanks. Did hook up a vacuum gauge and she idled at a constant 16. Manual says that may be too low and would indicate late ignition or valve timing. We may be on the right path! A buddy suggested I remove the catalytic converter. May be clogged. I use the truck for off-roading only so I don't believe I will need it. May try that first because I never checked timing before. Thanks again!

 

[ryanbass2]

Probably should do that...thanks. Did hook up a vacuum gauge and she idled at a constant 16. Manual says that may be too low and would indicate late ignition or valve timing. We may be on the right path! A buddy suggested I remove the catalytic converter. May be clogged. I use the truck for off-roading only so I don't believe I will need it. May try that first because I never checked timing before. Thanks again!

check your igniton modual and your coil i had a coil go bad on my 81 bronco did same thing it had spark but it was a weak spark if u get a yellow spark frm the coil replace it it should be blue