*EDIT* PROBLEM FIXED! Thank you!!

99 Blazer 4x4

Prior to installing plugs and wires the vehicle was having a very hard time starting. Connected a diagnostic tool and the only error code received was a bad catalytic converter.

Installed new spark plugs and spark plug wires. (Gap was set to .060)

Now, the vehicle is turning over just fine (as it was before), but still having a very hard time starting. Once the motor fires up, it's idling *very* rough and there is a small knock that I believe is coming from the drivers side of the block/head area. This noise was not there prior to changing the plugs/wires.

Did a short test drive and it's just running awful.

And, the speedometer is now stuck at 100, as well. (might just be because i removed the ground on the battery during installation of the wires?)

I have a Haynes manual and I cannot for the life of me find any info for the speedometer to retrace my steps to see if a sensor/wire/plug was accidentally removed in the process. I'm hoping that possibly a ground was popped off or something simple that would be causing this!!!

I'm really hoping that someone here has experienced this problem before or may know what's going on and can send me in the right direction.

Thank you!

 

are you sure you put the plug wires back in the right order?

 

that was my initial thought... and after triple-checking them, i'm certain they're in the correct order.

distributor:
c
6 5
4 1
2 3

cylinders:
c
6 5
4 3
2 1

 

Are all of your vacuum lines connected properly? All connections to the intake duct between the throttle body and MAF sensor connected properly?

Have you cleaned your MAF sensor and EGR valve?

What was the specific code that you received?

On the speedo problem... It would be quite remote for your work under the hood to have messed up something with the VSS and/or gauge cluster itself, but stranger things have happened.

 

Thank you, all for your responses. Took everything back out, reinstalled everything and it worked like a charm. There were actually two issues. First being the 6 and 1 plug wires and how tight they are (the 2 longer boots)... they sure don't seat very well and it took some extra grease and they went right on. The second issue was in fact a loose vacuum line!

Again, thank you!!

 

Great you got it fixed but I'm still wondering about that speedometer.

 

It's still a wonder to me, as well. It fixed itself.

 

Sorry, I know this is an old thread but I wanted to comment since there isn't much out there on this problem & others might be looking for answers too..

I just completed the dreaded lifter replacement tonight. After getting everything buttoned back up I started the blazer & let it idle. I watched the oil pressure, listened to the engine & held my breath.. My #6 tick was gone (yay! ..broken lifter cup, #6 intake) but I had a new tick in the same area as the OP described (drivers side, mid-head).. I just contributed it to one of the new lifters not pumping up yet.. After a few minutes, engine good & warm, tick still there, so I brought the rpm's up a little.. The engine was missing, cutting out & shaking badly off idle. I was like WTF??? I peeked in at the oil pressure gauge again & noticed the speedo pegged out at 100 (good pressure though). I hadn't noticed the speedo up till this point, but wasn't looking for it either.. I didn't know what was up but I figured it was computer related..
The only thing I could think to do was unhook the ground cable again & let it sit, hoping to reset things.. In the meantime I changed the oil, topped off the coolant & looked over the electrical connections..
That did the trick! I guess it just wasn't happy with things when I originally reconnected the battery. Now it's quiet, idles smooth, sounds good & feels good..
Mission accomplished!