rough idle&stalling, Help?

[Mark & Michelle Sousa <mps@netpci.com>]

All was okay when I replaced my crankcase hose. I was able to remove
the dipstick and the engine would recover. Now all is bad, sometimes she
can barely
recover and sometimes she stalls. I've checked my hoses and all seem
okay. This
started when I replaced the damn fuel check valve on the fuel pump (new
pump assembly on order) the valve I put in was slightly smaller in size
than the one I took out. any ideas on what happened ( I know, if it
didn't look the same I should of left it alone)?

My other problem I have never been able to figure it out, according to
the Bentley and
other shop manuals (Mitchell) when the A/C is on my rpms should kick up,
this
has never happened instead they drop, and slowly (not all the time ) it
may level off back
to about 780 rpms.

Last but not least I continue to have my hardstart problem (after I
replaced the
check valve the engine began stalling right after startup). Is there a
component,
that is related to all this (besides the fuel check valve)?

I have replaced the following:

1. ISV
2. Plugs (tri-electrode)
3. Plug wires/distributor cap&rotor
4. Fuel check valve
5. OXS
6. Timing belt
7. Temp sensor
8. Crankcsae hose

Mark (dazed and confused but beginning to get annoyed)

90 200T