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stuttering 2.8

575 views 2 replies 3 participants last post by  Hammerdown 
#1 ·
My 87 Jimmy 2.8 just started acting like it is vaporlocking, it's either a fuel delivery problem, or ignition.
It runs great, when I first start it and drive for awhile but starts stuttering once it's warmed up, which has me thinking its a sensor. The engine has 160K on it and normally runs great, I have never changed out any of the sensors so I am thinking of starting with the MAP sensor, and then the O2 sensor, the plugs are maybe 2 years old so they would be next on my list (but if one was fouled it should not run good until it warms up
), does anyone have any other recommendations?
I believe the KEY here is that it runs great before it warms up, and I THINK that the sensors and computer don't start doing there thing until its warm?
 
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#2 ·
You might want to check to make sure that your EGR valve is opening and closing when it's supposed to. When that valve reaches a certain temperature it's supposed to be wide open, I do believe. A vacuum check on the valve will let you know quickly enough.

Also, I don't know if they had them on Chevy's but on F*rds I know that there were some sensors along the injection system (if you have injection) that might be the cause.

Then there's the typical O2 sensor check, and then perhaps the fuel filter!
 
#3 ·
Once the ECCS goes into "Closed Loop", it reads info off all computer-controlled sensors.
I'd start out by buying a Chilton's Manual at Autozone, Checker, etc. Chilton's is the best repair manual I've seen for a novice repair guide.
Start out by jumping active computer wires on the ALDL, and ck for "Trouble Codes". Typically, when a sensor like MAp or O2 fails, it'll store a "Hard Code" in the computer, leading you to the repairs needed. That way, you don't have to throw parts at it and hope you find the right one.
Another thing you can do is buy a cheapie Code Retrival Tool at Autozone or...

Easy stuff!
 
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