'90 200 TQW cavitating, and jerking...

[Ivan Tuma]

Hi everybody ... I'm wondering if any of you recognise the following 
symptom on the '90 200 TQW.

Just trying to get some concesus that I may need new fuel injectors...

I have new plugs, wires, distributor cap and rotor ... replaced #1 knock 
sensor recently. I have no engine fault codes
being registered in the MAC-14 at this point (4444 flashes out after 
running the car and following the SJM web site instructions).
I do have a high-performance wastegate spring installed and I get 
anywhere from 1.4 to (sometimes) 1.5 bar of boost at full throttle.
I'm in the process of working on Ben Swanns resistor mod. My resistor is 
switched and right now it is turned off (stock config) and I have
yet to install the pressure regulator for the wastegate, so the 
wastegate frequency valve is still in place and operational.

Under moderate to hard acceleration, the car sometimes runs perfect, but 
others, like today under hard accelaration, it actually jerked. Other
times it sort cavitates during accelation ... almost like it's pulling 
back the timing up through the rev range. The check engine light is not
coming on during this however.

Here are some other symptoms...

- Moderatelly hard starting ... takes about 5 turns to start when cold, 
or if it's been sitting for more than 20 minutes. Subsequent rough idle 
for a few seconds.
- Sometimes it will idle ... seemingly on only 4 cylinders. A few hard 
revs seem to clear it's throat ... sometimes.
- Colorado State emmission test passed after second try ... had a hard 
time finding a balance between HC and CO. It passed but CO was on the 
high side.
- Normally I run with an octane boost since colorado gas only goes to 91 
octane. Right now, I'm not running any octane boost, and I got actually 
got the jerk on accellaration vs. the usual cavitation (surging).

Ultimately, has anyone had bad injectors cause pinging? Is this somewhat 
common? Is anyone selling injectors for around $25/piece? Since I'm not 
registering fault codes, I'm assuming that the pull-back could be caused 
by the knock sensors "hearing" a ping.

Thanks in advance for your input.

Ivan