1988 5.7l TBI idles @ 1800 RPM

I recently purchsed a 1988 Chevy G 20 conversion van with a 5.7l TBI and TH 400 tranny. When I bought the van it was idling high and a friend of mine
hooked it up to his Snap On scanner and got 4 codes, 15,22,44 and 45. I replaced the Idle Air Control unit, the ECT sending unit, the O2 sensor, and the idle is unchanged. What else could it be ? Please help, I have to drive this thing to Florida soon !
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
a vacuum leak...

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Check the TBI to manifold gasket; they go bad on a regular basis. It should cost you less than three dollars for a gasket and take about ten minutes to replace.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% There are two classes of pedestrians in these days of reckless motor traffic - the quick and the dead. ~ Lord Dewar 1933 ~
Climbing into a hot car is like buckling on a pistol. It is the great equalizer. ~ Henry G. Felsen 1964 ~
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
You missed code 22 this is the tps sensor voltage too low, this can set code 45 , the code can be set because of the low tps readings.

-
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks for the help. I changed the TBI to manifold gasket. Idle is much improved, but still too high by about 200 rpm or so. Another problem has reared it's ugly head though... Wisps of light blue smoke when first started { valve seals maybe} which turns grey during idle[ not terribly much but noticeabe} then changes to rich, thick brownish grey when the pedal is mashed, much worse when you let off the pedal. I changed the PCV valve and it is not as bad. I have been a firefighter for 20 years and have been in house fires that din't smoke that bad.Any suggestions ? Maybe a grenade ?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.