EA82T misses between 2500-4500rpm if i step on pedal or pump on it

[BoostedBoxer421]

Hi, I have an '87 GL Turbo, and if I floor it or pump the accelerator between 2.5k and 4.5k it starts to miss and sputter, but if I gaive it say 3/4 throttle, it will rev up perfect

 

My first thought was the intake was leaking because it started in boost range (boost light comes on at 2k every time) but can't find any leaks..

 

Timing advance? Bad pcv letting air in before turbo? Maf sensor? Idk what to check now..

 

-Thanks fer any help! Just got two feet of snow at my house and my wagon still goes anywhere!

[naru]

Weak fuel pump/clogged filters.

Measure the fuel pressure on the fly if you want confirmation.

It should maintain 43 psi at full boost.

I would bet money it does not.

 

Don`t pump it.It is not carbed.

[BoostedBoxer421]

Fuel pump is stock and pretty weak. I have new pump I bought for my '87 RX to use though

 

And not pumping pedal to keep it running, just noticed it while driving on ice and through snow lately

[86 Wonder Wedge]

I'd double check the timing and hook up an analog boost gauge to make sure the pressure is not spiking. These are equipped with an overboost switch which cuts the fuel (which is a bad idea, IMO. Should be an ignition cut) when the boost pressure is too high.

 

Otherwise, check the normal rubber parts for cracks and check the TPS for smooth operation and consistent resistance readings.

[BoostedBoxer421]

going to get boost gauge, but as soon as i pulled TPS off it kinda crumbled in few pieces, so other than weak pump i may have found my problem with that.

 

and recently change both timing belts.. when i check the timing with a light the line kinda wavers about 2* back and forth going from about 17*-19* :/

 

this engine has 235,000 miles all stock and runs great. i plan on going over as much as i can to restore it