Ok, I bought my 90 cummins back in april, and other than the speedo and the alternator it has run like a champ. When i first got it my boost peaked at 15 psi but since then it has dropped and wont go above 10 psi. it is intercooled but idk if that would effect it or if the boost gauge might be off. Any ideas?

 

you might check your boots...and or gaskets to see if you have any leaks?

 

Yea I think hes right there, a whole in your boot could realy make you lose a ton of boost. My buddy has a 94 and he grinded a **** load off his plate and slid it all the way forward turned his star wheel and got some laser cut injectors from a friend and still had that whole is his boot was barely if not at stock power and our friend he got the injectors from did all the same mods and had around 400-500 hp and got 19-20 mph while my friend with the 94 is gettin 15 mpg with no power, but before he turned it up he could barely even make it up a hill with out puttin it in third. Well just my 2 cents.

 

Ok thanks, ill give it a shot and see if anything leaks