Strange misfire

[lostmartian63]

I just changed the dist cap/roter, plug wires, plugs, fuel filter and a couple of vacume lines that were dryrotted on my 89 s10 blazer 4.3tbi 4x4 and now it has a slight miss to it. It doesnt sound like its on the same cylinder because at idle on the same rpms it misses at different interavles like the ignition coil is going bad. I know its not the wires being on the wrong cylinders because that was my first thought so I checked and there all good. Has anyone had this same problem? If so what did you do to fix it? I also have been meaning to run some seafoam in the oil to clean it out and some injector cleaner to clean out my tbi injectors because the previous owner was and old lady that didnt know the exhaust from a windsheild.

[lostmartian63]

Ps. this miss could have been there before and I just didnt notice it because the thing ran like crap because the fuel filter had NEVER been changed I think the plugs and wires were about 4 or 5 years old because I acctually had to use penitrating oil to get one of them out it was so rusty.

[OverBoardProject]

If you haven't checked the timing that's the first thing to check.

I wouldn't be suprised if the plugs and wires were the origionals, which I see from time to time.

I haven't tried Seafoam, but I've tried simular products and recomend them all.
I personally keep away from STP.
Injector cleaner might clear up your miss too.

I'm just guessing that your Blazer was really affordable, and has very little milage on it.

[lostmartian63]

Yeah its going to the shop monday for a timing check unless there is an easy way for me to check it. The blazer has 143k miles and i paid 400 for it because the back window&tailgate were f'd-up. All in all I think I got a good deal and I really like the truck.