A friend of mine who's part of the "older generation" who doesnt use computers asked if I could post for him a question about his 99 chevy blazer s10 with a 4.3l vortec.

Basically when the car is first started up it idles rough and even when stepping on the gas pedal it sort of hiccups until it's warmed up after it runs for about a half hour it's fine. I pulled a few codes off one being an o2 sensor and the other being an evaporation code which has been on for a few years.

We have changed out the spark plugs and wires and didnt seem to help. Didnt want to spend the money on a coil if it wasnt that and same with the o2 sensor but if that could be the problem he will try it.

Now he also has another issue that if he lets the fuel pump fully kick in it floods out one of the cylinders and wont start at all so we just have to put the key in and turn quick otherwise we have to remove the plug from that one cylinder and let it dry out for a few hours put it back and it starts up no problem. (this has been an on going issue for a while now and just hasnt figured it out but he knows the trick to not let it happen so thats not a major issue for him)

I'm thinking it's an electrical issue as far as the running poorly when damp and cold but just havent pin pointed it exactly as to where or what it could be, and thats why I'm here looking for a bit of advice.

Thanks

 

Sounds like you need a new dist. Cap and rotor. The poor running when damp is a classic symptom of bad cap and rotor. I would do a fuel pressure test for your other problem.

 

Agree with 50lb,but also consider new ignition wires and use dialectric grease at the cap,plugs and coil! Very important to keep moisture out of these connections!

 

what you guys think about that cylinder flooding out? ever hear of that?

 

had the same problem, it wouldn't accelerate and had really bad hesitation like a wiring issue, turned out to be 2 of my O2 sensors were gone
changed the sensors myself less than $200 for parts, my truck had 4, with the code reader and the manual it was a quick and easy fix

good luck

 

Symptomatic of a leaking fuel pressure regulator or spider assembly. Read through this thread:

96+ Fuel System Diagnosis