Idle problem

[Tyke]

I cant get of the couch .... no not really

1994 K 1500 4x4.

Had an issue last year and replaced ICM, plugs, Cap, Leads, oil pressure sender.

That cured the stalling problem.

Recently I did a full TBI refresh. Replaced both injectors, full service kit and good old clean.

Since doing this there was good news and bad news.

Good news, engine now runs much better and is returning around 13mpg around town ...Score !

Bad news, engine has started to hunt badly when performing very low speed maneuvers like reversing, coming slowly to a halt at stop sign etc. mostly the engine dips off the rev counter (below 500rpm) but very occasionally it will stall.

When installing the TBI kit and injectors I followed the process described in a couple threads on the forum and a Youtube video.

I wonder if I missed something or perhaps should simply turn up the idle??


The truck has 225k miles but is very well maintained and otherwise runs like a top.

Any help or insight would be a great help.

 

[Schurkey]

Verify initial timing, and timing advance.

Verify fuel pressure

Connect a scan tool, look at all sensors but especially TPS, MAP; and make sure IAC works.

Did you dick with the base idle screw? If not, leave it alone. If you did, follow the idle setting procedure in the service manual. Idle speed is controlled by the computer via the IAC, but that assumes that no one has messed with the base-idle screw.

 

[Erik the Awful]

Bad news, engine has started to hunt badly when performing very low speed maneuvers like reversing, coming slowly to a halt at stop sign etc. mostly the engine dips off the rev counter (below 500rpm) but very occasionally it will stall.

Check for vacuum leaks.

 

[Tyke]

Verify initial timing, and timing advance.

Verify fuel pressure

Connect a scan tool, look at all sensors but especially TPS, MAP; and make sure IAC works.

Did you dick with the base idle screw? If not, leave it alone. If you did, follow the idle setting procedure in the service manual. Idle speed is controlled by the computer via the IAC, but that assumes that no one has messed with the base-idle screw.

I did not touch anything settings wise on the throttle body. I do not have access to scan tool, so I assume this is a trip to a mechanic?

 

[Tyke]

Check for vacuum leaks.

I did that to the best of abilities without the correct gauge, again from what I'm hearing this could be beyond my scope now and time to visit a shop