Need help

[Jason87 v10]

I have a 1987 v10 custom deluxe 5.0 tbi it I recently started having a hesitation while driving where the check engine light flashes for a second and the engine sputters then goes right back to normal. It happened rarely at first but has started to happen a lot in the past week or so. The truck starts and will idle just fine and you can drive it but sometimes it sputters a lot while driving and on some trips not at all I have changed the plugs and wires, ignition coil, fuel filter and am currently running Lucas fuel treatment through it still having the same problem but seems to be getting more frequent. So has anyone else had this problem or know the cause

 

[Georgeb]

First you need to check for a code. Check out this thread and report what you find.
http://www.gmsquarebody.com/forum/showthread.php?t=2315

 

[Jason87 v10]

No code

I did that a couple days ago and it is not showing a code just the diagnostic test active code which is 12

 

[1987 GMC Jimmy]

But you're getting a check engine light intermittently? And you're saying that all you get are twelves? Hmm, it may be the ECM on the fritz. You can pull it, open it up, and check for scoring or burning in it to see if it got damaged. That's a telltale sign, and that's worked for me before. It's behind the glovebox, and it uses quarter inch bolts. Make sure you give it a good look over.

 

[Jason87 v10]

So after changing the fuel filter it ran great for 2 days then on the 3rd day it started up again this time a little worse meaning more frequently I am going to check the ecm now has ant one else had this problem

 

[1987 GMC Jimmy]

I've had that happen on my Caprice which uses the old CCC feedback carburetion system. It would sputter, bog, and accelerate poorly. It would idle fine, however, and it would cruise okay. I opened the ECM and one of the integrated circuits had burned up so I replaced it. I think there's a short somewhere because I can't communicate with the computer, but the car runs great.