2003 stock evo VIII

Hesitates on hard acceleration between 3500 & 4000 rpms.

Coughed this morning in 4th gear when I tried to pass a semi-truck.

No engine error codes.

Please help.

 

Boost leak test is in your future, along with checking your plugs.

 

Plugs are new. Wires and coils are not. Problem remained after plug change.

 

Boost leak test
Test coils and wires

 

Was thinking about nology plug wires. Maybe now is the time.

 

Stupid question but you did gap the plugs when you changed them right?

 

Sounds like a boost leak

 

This could be a host of things. Very good advise above...I just went through similar problem. Mine turned out to be the stock fuel pump circuit. I obtain a DW 300 fuel pump..same problem so I hard wired the pump...same problem. The problem got worst....the car would stall. I would let it set for awhile and then it would start. This time I put my own hard wire circuit, bypassing the stock three relays and resitor. New relay....fused straight from the battery.......retune....all is good now. Have no idea if this is your problem, but something to think about. Good luck!

 

Make sure there are clips are holding your intake snorkle to the rad support. If not it'll lift at speed and cut air flow

 

I spoke too soon! Now it's starting when it wants too? Just started this again to day. I can hear the pump running, but no start issue. Nuts!

 

Ohm out your wires..... most likely they are bad. Did you notice the terminal end of the old plug?(black)

also gap them correctly. pre gapped are not correct for evo specs.