Stops revving at 2000

[andrewjscott]

whats up everybody.

I'm having a bit of a problem and am getting pretty frustrated.
it's a 91 talon tsi awd and i'm having stuttering issues between 2000-3500 RPM. The car idles rough, i can give it a bit of gas and it'll start to rev up to about 1500, then basicly stops reving around 2000. My autometer boost guage reads 0 PSI, my stock guage is reading more than 1 bar. if i give it too much gas it will stall out. if i feather the throttle it will slowly (and i mean slowly) gain RPM up to around 3500 (takes about 30 seconds or so) once i hit 3500 RPM, engine revs normally. During the stumbling it blows a bit of black and smells of gas. No codes are present. No vacuum/boost leaks. a mechanic at work thinks its something electrical, seeing that its blowing black I would assume its the ignition system. I've got new plugs/wires. I suspect the coil or power transistor and i'll be testing those tomorrow at work, but would either of those parts cause this failure in a certain RPM band? and shouldn't either of those parts set a code if they were failing? Any help would be greatly appreciated.

 

[absolute_DSM]

Check your TPS as well for dead spots.

 

[ob420aboosted]

deffinitely check the tps first.

 

[andrewjscott]

thanks for the replies. I will do that once I get to work. Only thing I don't understand is if it was the TPS, shouldn't that set a code aswell?

 

[JeffGST]

Not being able to rev past 2000 RPM sounds like an airflow problem. I would say that the ECU is not getting a Hz reading from the MAF, but then again that would have thrown a code.

Possibly a massive boost leak after the MAF. The ECU is reading and calculating airflow, but it never reaches the motor through the leak. This would explain why feathering the throttle does not cause this and a good amount of throttle would cause the sputtering.

Boost Leak test it.

 

[andrewjscott]

It was an airflow issue. I pulled my MAF and cleaned it up with some intake cleaner. no issues anymore.