Hello guys
I have a 1986 Blazer K5 305 V8 with 45000 original miles that I bought new in 86. I am recently having trouble with no power and hesitation issues. The blazer starts fine, then after about 20 minutes of running engine starts to hesitate with very low power. Only changes that have been made were that I had dual exhaust installed a year or so and ran fine up to now. Other than that the Blazer is stock. Did all the routine maintenance, fuel filter, air filter, looked for vacuum leaks and still no resolve. It does have all that emission control stuff.
Any suggestions?

 

were the converters changed with the dual exhaust. ive seen a situations where the converter was clogged and just turned way worse when it warmed up.

also is the 86 a throttle body injection? ive seen the temp sensors go bad causing it to run weird when its warmed up

 

No converters now and ran fine for about 1000 miles until now. Not fuel injection, it's a 4 barrel carb. Thanks