Hi,

I'm working in fixing all the issues of a 1995 4door Chevrolet Blazer LT 4.3l CPI that I received from my old man, recently changed the spark plugs and wires, and the fuel pressure regulator that was leaking, also tried to clean the upper and lower intakes from all the fuel-dust that had been clogging it.

It has been running better, even if it only gives me around 7.5 MPG, but lately I have noticed a weird behavior, seems like revs are pulsating slightly,no more than 200-300 revs, and its only noticeable while idle when the engine is already hot.

I noticed this issue the last 2 days, so today I checked if any sensors connectors around the throttle body had contact issues, but I couldn't find any, except for the intake hose around the map sensor to be a little lose.

I'm going for a drive today, and will watch for any difference.

 

check vacuum lines for leaks

 

Thanks, I will check them again, maybe its some cracked hose, I just wish not to be the booster, I have had brake issues lately.
https://blazerforum.com/forum/2nd-ge...e-lines-87147/

 

After several years I manage to find the solution by accident seems that the injector spider started leaking some time later after changing the fuel pressure regulator, so I ended replacing a lot of things again:
Spark plug cables
Rotor and cap
Complete injector spider
fuel filter
And completely cleaning the upper and lower intakes, seems to be running rich but I expect for it to settle after a while.


Just cleaned upper intake



Just cleaned lower intake, new AC Delco injectors, new cap, rotor and Ac delco spark plug wires

 

Thanks for posting your follow-up, even years later. Follow-ups are very useful to others.

 

Wow....that sure takes me back in time when I had a '95. Always seemed to run rich no matter what I did. I too replaced the fuel injection spider and spent hours cleaning the intake. I swear that the new spider lasted about a year and then seemed like it started to leak again. I was going to replace it, but the '95 developed other problems so I just sold it and got the '02 I have now with the improved spider and intake design.

Good luck to you on your '95.