I also have a 98 and was experiencing similar problems, changed all the common parts, took it to a local shop asked them to check it out, thay had no clue. I suggest you take it to a shop that offers free estimates, there are plenty and have them hook up a computer to your Blazer and take it on the road to check for codes. This proved to be effective in narrowing itdown. If while driving you are pulling random misfires from multiple cylinders itcould possilbly be the gear at the bottom of the distributor as mentioned above. It fixed my problem. Good Luck

 

You might also check the O2 sensors on the exhaust manifold. I know that the code hasn't sent for them, but I have had an occasion when a broken harness to a bank1 sensor1 O2 sensor had been damaged. It was grounding out against the manifold and instead of an O2 code I was getting a whole bunch of other sensor codes.ie. Random misfire, TPS, CKP, IAT etc. At least you'll be able to take that out of the equation.

 

studentmechanic101

You are getting a good education now, huh?

At what point of replacing all these good parts with new ones are you going to stop listening to everybodies speculation and let a professional diagnose your problem?

 

The all-mighty Blasirstrikes again with his many words of sarcasm. Come on man if he didn't want to try and fix the truck by himself he probably wouldn't be a part of the forum. Besides thus far I have posted on quite a few topics and have recieved excelent information regarding repair. If I wanted to pay the money to have someone else work on my car I would, but not only do I not have that money, I don't mind learning a few things the hard way. Why don't you keep your unhelpful comments to yourself and allow each his own.

 

Actually blasir, I am going through the automotive technology program at the college in my area and I am ranked number one in my class. I believe I started off with a good start on my problem and as guywm25 said, he brought his to a PROFESSIONALrepair shop and they had no clue. I consider myself a professional and do have the top of the line in scan tools and I am going the exact route that any repair shop would. Apparently it must be a wierd problem because no one on this forum has figured it out and their are alot of very smart people on here. guywm25, I have pulled the codes as I am driving and the first code that will go right when it misfires once is crank position sensor intermittent signal (sorry cant remember the number) I have checked the harness and it looks good. I will have to check the o2 harness next. Thanks for the support almosteveryone. Matt

 

I, too, was told by a reputable repair shop to replace my spider injector...I didn't do it, though. Too much bread!

 

Look on the bright side Matt, there is a finite number of parts to replace on your vehicle. As gonzo says after you replace each and every one of them, "check" that one off of the equation. LOL

Sincerely,
"The all-mighty" Blasir

 

Has anyone figured out what this misfire problem is caused by yet? I own a 96 Blazer and I'm having the same issue with my truck. I've replaced cap, rotor, plugs & wires, fuel filter and still no luck. It's bad when I first start it up (cold) worse on rainy days & condensation build-up, and won't stop till it warms up. Then it only happens around 2100 rpms when hot. My first thought was cap & rotor, then I've been eliminating other options slowly. Next I was going to look at replacing coil then the ICM if that didn't work out. I get NO codes at all and my in-laws 99 blazer has the same problem but not as severe as mine has been lately. There's has been to the dealer for complete tune up with AC-Delco parts and frequent scans with no luck on finding the cause of this.

 

I too have this misfire bull! I am really pissed off! I am replacing the egr when it comes in I hope this is it. If not I will post. What is the gear on the bottom of the distr. that goes. How do yo change it?

 

I too am having a similar issue, when it tries to start there's a popping or misfire sound, and the exhaust reeks of gas. I think this actually may be the fuel spider, but who knows lol...good luck with your issue