Very rough idle at startup (only), then stalls

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Mar 27, 2003
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Ok payday is Friday, so I'm going in tomorrow to make an appt. at the Dealer. The phantom stall had dissappeared so I thought. In the last 24 hrs though it has stalled 3 times while in park, and 4 times while cruising down the road slowly, usually shortly after taking off from a light etc.

Latest behaviour:

1 ) Very rough idle upon starting (starts up easily though first time, every time)

2 ) Idles normally for first 30 seconds of startup, and then the needle dips dramatically a few times before it just stalls.

3 ) When this happens if I press the gas gently it will more or less smoothen out the idle.

4 ) Once it decides to idle normally and I take off slowly thru the underground garage and into the street, its as though it has a very subtle surge going because I can get out of the garage , into the street and down to the light easily without ever hitting the gas pedal!

5 ) Once I am off though and the truck has settled down (5 mins or less) it seems to run like a top. Only problems seem to be upon starting from cold.

A few perhaps unrelated details I'll mention:

1 ) My accelerator linkage (engine side) seems to have some slack in it. As it lays at rest it has a slight sag downwards. If I lift up on the wire it will easily travel a 1/4" before actually affecting the throttle.

2 ) The purge line from the emissions canistor is pretty loose at the engine. By moving the line I can easily twist the connection at the engine. In fact , with the engine off, I was able to just pull the line right off the engine without any problem.

So only a problem on recent cold starts ... and then followed by a slight consistent surge for a few blocks.


TY
 
T Y L E R,

I pulled that purge line from the canister, drove it for a few minutes, and it doen't create any problems. I don't think there is very much vacuum on that hose; certainly not enough to to create the problems you are having.

I suppose you've already checked the large hose that goes from the intake to the air filter canister?

-B-
 
I'll take a closer look tomorrow Beo.


The really odd thing is that after driving to the Lake for a few hrs and idling as I surfed etc I headed home and when I went to merge onto an expressway and twice when I hammered it the 80 literally flew! Obviously I live with this 80 day in and day out and I can say that it hasn't jumped like that for several years. So did I inadvertantly do something today at the lake when I lifted the hood and started tuggin on tubes and wires .. looking for a culprit?

Say it ain't so ...



TY
 
Be sure and check for a cracked intake hose - sucking in extra air post air meter causes the symptoms you described. Also check the wiring harness for any signs of melting - particularly where it goes down through the intake plenum ...

Good luck!

Tucker
 
This may not be too helpfull but, my previous vehicle had simillar symptoms and it ended up being the ECU. It was the ignition control that was flakey. Nothing I could do short of replacing the ECU.

Have you tried to reset the computer?
 
Check the power to the ignition switch. There could be some type of intermittant open happening in a connection. It happened to me. The fusable links could be bad or the ignition wiring harness maybe mangeled because of PO.
 
tyler next time it happens check and see if your temp gauge does anything. Otherwise I agree with the comments above.
 
Both your listed points are normal.

I would guess the intake hose has a bad crack.
 
:doh: :doh:

The oil was down a bit so I headed over for some 0W40 M1. When I had the hood up I checked things over a bit closer. Dang if the intake hose wasn't LOOSE! The distal end was askew and the top portion was angled back about 1/2". Both securing screws were also poorly tightened. I took care of it, and am hoping that will remedy the stall gremlin.


Thanks for the suggestions.


:beer: :beer:
 

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