[Ford junkie 89]

Ok iv got a 90 lx 5.0. 306 bottom end ford svo heads stock bottom end 24lb injectors edelbrock intake 74 mm throttle body cold air intake with 176 l&w rockers. It starts an idles good but anything above 1500 rpm it starts poping an back firing sometimes miss firing. so Iv traced everything changed plugs changed plug wires checked 6AL box checked distributer check alternator check coil pack checked fuel pressure checked rockers checked pushrods checked everything without tearing in to the bottom end. Now before Ido that does anybody anything that I may have missed that could be making it act up like it does I mean you can't drive it it's so bad. Any thoughts or input is much appreciated. Thanks

[Ford junkie 89]

Originally Posted by Ford junkie 89

Ok iv got a 90 lx 5.0. 306 bottom end ford svo heads stock bottom end 24lb injectors edelbrock intake 74 mm throttle body cold air intake with 176 l&w rockers. It starts an idles good but anything above 1500 rpm it starts poping an back firing sometimes miss firing. so Iv traced everything changed plugs changed plug wires checked 6AL box checked distributer check alternator check coil pack checked fuel pressure checked rockers checked pushrods checked everything without tearing in to the bottom end. Now before Ido that does anybody anything that I may have missed that could be making it act up like it does I mean you can't drive it it's so bad. Any thoughts or input is much appreciated. Thanks

Thinking it maybe a rod bearing even though it still holds great oil pressure an Iv also do a compression check an it has great compression.