i have a 1998 Olds Bravada with the 4.3 vortech. I have been getting it ready to go cross country in 2 weeks and it seems like everything i do to it makes it run worse. I have replaced all 3 O2 sensors, Fuel spider, plugs, wires, and mass air flow sensor. It ran pretty good but started to lope at idle and was throwing a random misfire code. So today I put on a new cap and rotor, now the damned thing pops when at idle (didn't before). When replacing the cap and rotor i noticed some play in the dist. is this normal (turning play if you know what i am talking about). Please someone help me out becasue i NEED this thinkg to make a 4000 mile round trip in 15 days

 

First make sure you put the plug wires on in the correct order. Have you checked the fuel filter? Idle issues could be the IAC needing cleaned or the EGR needing cleaned. One thing I have heard over & over is that using OEM plugs is the only way to go. (AC DELCO PLATINUM PLUGS) That Bosch & others don't work real well.
Just my thoughts. Hopefully someone will post up that has had more experience with Blazer tuning problems. My 97 Blazer 4x4 has run basically trouble free since I got all the bugs out of it when I bought it 2 years ago & 55,000 miles ago.

 

i replaced the plugs with champions because that is what came out of it (looked good when pulled)

 

your distributor gear might be worn causing play and the misfire.

 

What I know is I have read over & over on this forum about using OEM plugs. People have had problems using others.
I don't know from any experience because when I tuned our Blazer I used AC Delco Platinum Plugs which are what they came with it.

 

I had problems with Bosch plugs, I replaced them with AC's and it made a big difference. I only used standard AC's and will be changing them out for the AC platinums to see if it helps with the remaining issue I'm having.

 

after about a week letting it sit and get the best of me I went and checked all of the plug wires and alass i had 2 crossed up. It is running fine now but that pesky service light is still on and it cuts out every now and then but I am going to ignore all of that and proceed with my trip. thank you all who helped out

 

Glad you found the issue. Get the code read and we'll see what we can do about what's setting off the light now.

 

right now there are 2 random multiple misfire and idle higher than expected. I took it for a 4 hour drive to pick up a set of rims for my amc and when crusing on the freeway with the cruse set it will miss about every 10-20 miles.

 

vacuum leak? dirty injectors?