2003 gtx 155 surging until 5000 rpm then holds steady

[tswisher21]

This has always done this sense i owned it. It wont cruse less than 30 mph or 5000 rpm. the rpm"s surge below that. I have found a few people who had the same issue but no one has stated what fixed it. Did anything fix it. No i dont have an exhaust leak,i rode it with the seat off and it still did it. After you get it over 5000 rpm it holds the rpms fine and it runs fine. Thanks Tim

 

[tswisher21]

sorry its a 2002 if that matters.

 

[Digdog]

Probably the throttle body , sometimes you can lube it but usually it needs to be replaced. If you have a intercooler check it for leaks

 

[POPPS]

Could be fuel related,,, I would check fuel pressure, ,,then pull the fuel rail to see if all 3 injectors are firing,,have a equal nice conical spray pattern.,,you may need to get the "BUDS" unit to diagnose this fault..there are many sensors on the 4 tecs,

 

[Eric Von]

I have a 2005 155 same thing going on. Runs awesome but get the surge between 4500 and 5000 rpm. Been like this for years . I’ve learned to accept it as I can’t trace the problem. If you figure it out please let me know. Thanks

 

[POPPS]

If you have ruled out any fuel issues,,,perhaps the main rear oil pressure switch is failing,,,if is the original,,,they are cheap and easy to replace,,,and easy to eliminate from your equation,,,

 

[CraigAllen]

I have a 2005 that does something similar but stops running altogether after 20-30 minutes. It feels like it loses power during that time too. It “pops” at quarter throttle but I can mash it wide open and no problems at all.