Help with rough idle.

[bigblue87]

I just purchased my self a 1987 chevy 4x4 about a month ago. I Fell in love with it when i first seen it, so i had to pick it up. Everything with the truck is pretty decent considering it was used for the past few years as a daily driver.

So to the point, i'm having some rough idle issues i was hoping you guys could help me figure out. the truck is shakey in neutral and drive at idle speed and even seems like it wants to stall once it warms up to normal temps. I think it smooths out anything over 1500-2000 or at least it seems to.
Here;s a list of things i have checked/replaced.

87 350 w/TBI

- replaced plugs and wires
(Not sure if it was my imagination but when i fired it up after this it seemed to run good until i started it up again the next morning)
- checked the distributor cap
- checked timing
- checked the in injectors spray pattern and ran seafoam through it
- checked for vacuum leaks (hoses and around intake)

After that i figured it might be a sensor so i fixed the SES light and came up a few codes (44(02 sensor), 32,and 34)

So i have replaced so far

- o2 sensor
- Throttle positioning sensor
- temp sensor
- IAC

Found out that the egr wasnt even hooked up to the TB... didnt think i even needed it but figured id hook it up any way. It ran even worse than before so i ended up just replacing the egr as well.


I think thats about it. If any one has any words of wisdom id love to here them.
Thanks!

[walkerscott]

use a timing light and inspect the injector spray pattern
they should not spray large droplets

an adjustable timing light works best

[beamn7]

Remember to unplug the single wire in-line connector when checking the timing. Brown with black tracer if I recall. Believe timing on these was 0 deg. Been awhile though.... Also inspect the pole piece (magnet) in the distributor. GM had a bulletin out on these for water / moisture intrusion and the fix was to use a marine style cap if I recall.... Could be some rust, etc on the pole piece below the rotor.
Nice lookin' truck!

[walkerscott]

you are correct if your checking timing

but for this procedure
dont unplug the connector

your checking the spray pattern of the injectors sorry for not being clear .. you will see stuble when the injector drips

[grs]

It could need a valve job. Take a piece of index paper, and place it on the end if the tail pipe. The paper should flutter nicely. It it makes a popping sound, and does not flutter nicely it needs a valve job. It could also be bad plug wires.

[bigblue87]

I did take the cap off and inspected everything...seemed to be decent .
Did the wires unless unless i toasted the new ones some how.

As far as valves i was planning on doing a compression test.