I'm having a problem, and i've run out of ideas for what it could be. Everytime I hit around 1900rpm the car hesitates, almost like a slight miss, and it continues to about 2800rpm. After 3000rpm no problems at all. It happens in every gear, if I throttle it slowly or quickly. The exhaust also has a weird higher pitched tone (even at idle). It's a 98 with a 99 motor, 98 DIS and fuel system. It's run fine for over a year with this setup.

Here's what i've checked:

Ignition working at all rpm (spark)
Injectors are clean/working
all vacuum lines connected/no leaks
all sensors/electrical connected
NO CHECK ENGINE LIGHT

I dont know what else to check. I've thought about the cats...maybe one is clogged. Would that cause a problem at these specific rpms? I havent checked compression yet, mainly because im afraid to.

Any ideas??????

 

Take the exhaust off and check it out. Do you still have the stock one? If so, put that one on and see if that helps. Between 1900-2800 does the exhaust sound different (abnormal)?

 

Could very well be a cat, any weird smells coming from the exhaust or normal? New rattles?

 

Time for an off road x-pipe.

 

If there were a dead spot in the cam/crank sensor it would happen throughout the RPM range.

 

If it was a clogged cat would'nt do it at all RPM's?If you checked everything else,do a compression test.

 

If it were a clogged up cat you may not notice it at lower RPMS because it doesn't need as much flow to idle. At higher RPMS the air could be forcing it's way through there enough to not notice the rough idle as well. When you let off the gas does it make a weird noise?

 

I think if it was something like that it would have thrown a code.