Hello all. I've got a 2wd '92 s-10 blazer with a 4.3l TBI vin z. For a while now i've been chasing down a problem. The engine would start, but as soon as it started it would idle extremely rough and almost stall, catch itself and then repeat the process.... it usually wouldn't die but it happened on occasion. I replaced the MAP sensor thinking that might do it, then i replaced the EGR, and finally I replaced the EGR vacuum solenoid. And after having replaced the solenoid it ran PERFECT for about 2 days. After 2 days I noticed dramatic loss of power while accelerating, and then last night when I started it, it would start fine but after a few seconds the engine would start to struggle to stay running, and reving it just brings it to a sputtering stop.

I thought that the EGR valve i bought might have messed up, so I put the old one back in after cleaning it out really well with carb cleaner(since i had determined the originall problem was the vacuum solenoid for it). And there was no change. The problem isn't quite the same as what i had chased down prior to the repairs, the frequency of it catching itself and falling back is MUCH more graduall.

Does anyone have any idea as to what the problem could be? Could that new solenoid be causing this new problem?



---- EDIT----


Well, I ended up doing more work with the truck. I thought it was the o2 sensor so i changed that, and of course it wasn't. So I was just fiddling with things and I ended up disconnecting one of the vacuum lines and started the car to see what would happen. When i started the car it ran fine, and then i put the vacuum line back on while it was running, and it went back to its really weird idle. I don't really understand why it had this effect since the vacuum line being off would cause the problem to be worse( at least thats what i thought)....

So now i've got a bit of a different problem. This vacuum line i'm working with starts on the engine block pretty much right beside the MAP sensor and connects to 3 things. It goes to my windshield washer fluid pump, a sphere that has no connections other than the vacuum line( even if yall don't think this is the problem could someone put a name to it? its been bugging me for a while now), and then there is a very small line that goes into a bundle of other wires and then through the firewall(If anyone knows where this one ends up that'd be pretty helpful too). Anyone have any ideas as to what could be causing my car troubles?

 

Sounds like a vaccum leak possibly have you checked all your hoses??

 

It also almost sounds like its choking out on fuel... Have you tried a new fuel filter? last tune up??

 

i went back and looked at the hoses, all of them looked good but something weird was happening with one, Instead of a new post i went back and edited the orginall. As for the fuel filter.... I believe it was some time this past summer. And I do believe she is due for a tune up.

 

Sound similar to my 92 S10 BLZR will not run w/ EGR hose connected, runs great w/o. Getting vacuum at idle, not good.