88 K5 TBI 350 (Code 32)

I have an 88 K5. This is the infamous TBI 350. The ECU keeps setting a code 32. Just started a few days ago. This would indicate an EGR problem? I have replaced the EGR vavle $$. No change. The code is
set in about 10min of driving time. Consistently! I just changed the EGR
vacuum control solenoid last night. Same results! Code 32 after about
10min of driving. I will change the 02 sensor this eve. After that I will
be looking for advice from you guys.
Thanks in advance for your inputs!

I would double check all the hoses. The diagnostic switch should close at about 2" of vacuum.

Try this,

Wear gloves cuz it might be hot,
With the engine running at normal tempurature, push up on the diaphragm. The engine speed should drop. If it doesn't clean the EGR valve and passages.
If the engine speed drops, increase the engine speed from idle to about 2000 rpm. The EGr valve diaphragm should move as this is done.
If it moves the EGR system is operating correctly.
If it doesn't move, attach a vacuum gauge to the vacuum hose connected to the EGR vavle (use a T-fitting to connect the gauge. Start the engine and increase the speed from idle to 2000rpm, then let it return to idle. At idle, approximately 6 inches or more of vacuum should be indicated.
If it is, the EGR valve is bad.

ALSO CHECK THE THERMAL VACUUM SWITCH!

I have the exact same problem going on with my 89 k1500. let me know if you find a fix...and I will as well. thanks

Petee

Had the same problem with my 89 Sierra. Changed out the valve, erased the codes and problem was fixed.