Hey guys, I've been gone a long time but recently got the Blazer running again and on the road. I have a '95 4.3L with the single central port injector (CPI/ 'spider'). I have always had issues with carbon particles and the EGR (runs rough and flashes the check engine light indicating misfire), but usually I run some sea foam through it and it clears up.

I notice however, that my fuel economy is very low compared to what it used to be (now in the 10-12mpg range) and it never fails to have the EGR carbon type of issues when towing my boat at highway speeds, loaded with 4-5 passengers at HW speeds, or even just steep highway sections with no extra weight (Tenn highways with steep grade). So I am wondering; are these issues carbon/EGR related (thinking that the added vacuum under high load is flaking off carbon deposits that make their way to the EGR and make it go wacky??)), or could it be a leaking CPI, the 'nut kit' (internal fuel lines within the intake), or a fuel pressure regulator? Does the fact that it only happens routinely under high load situations matter? With no or light loads at regular speeds around town, I haven't had the dreaded carbon problems in a while, but almost always do when I have some weight in or behind the truck at HW speed.

The boat btw is only 1280lbs dry, and with trailer, fuel, and gear we are looking at maybe 1800-1900 lbs.

Any thoughts before I pull the intake to look for leaks? Should I install the Temco or HELP! ERG screen and see if that changes anything? Is it worth changing the spider, regulator, and internal fuel lines once I have the intake off even if I can't find a leak? (preventative measure?) Any other things to consider for poor fuel economy?

Thanks alot!