98 Blazer misfires after intake manifold gasket replacement

Here's the deal. My 98 Blazer with 167K, W Vin, 6 cyl, automatic, was leaking coolant as fast as I added it. I figured it was a seal or a frost plug problem. I could not see where the leak was originating from, so I took it in for repair. The mechanic just bought this shop from his old boss, so he is now on his own. He replaced the intake manifold gasket (gasket set) which he said was blowing out coolant all over with a pressure test. Now, $582.36 later, my blazer is running very rough at idle, and misses when accelerating. It was not like this when I brought it in. I actually had it brought in on a car trailer, but even when I drove it onto the trailer, it was running just fine. The mechanic said the #3 cylinder was misfiring, and the rotor and cap were corroded. I had replaced the plugs about 10,000 miles ago except for the #3 because I couldn't get at it (I know how now after searching this forum). I replaced the cap (flat type) and rotor and there was no change. I will be replacing the plugs next, but my question is, do they have to remove the distributor shaft when replacing the manifold gasket and could have they put it back in off one notch in the gears which would throw off the timing? I will be calling the mechanic Monday about the problem, but would greatly appreciate any of your input on this. Thanks!!

Hi. my friend and I actually did the famous lower intake gasket repair on his 99 blazer. To answer some of the questions: yes, the distributor has to be removed in order to get to the lower intake mani.

It might be, like you said, that the distributor is a couple of teeth off. This happened to us whe we put everything together. all we did was loosen the dist bolt and turn it 180 degrees and the problem was solved!

have you checked that the ignition wires are in the correct order? hope this helps a little!

have you checked that the ignition wires are in the correct order?


Yes, I checked and all plug wires are correct and seated firmly. Thanks for the reply!

Yes the dist has to be removed and reset with a lower intake gasket repair.
Take it back and have the mechanic check it.
If he has a good scanner he can pinpoint the problem right quick.
You need to find out if it is a dead miss on one cylinder or other.
A cylinder miss will show up on a scanner.
Also ask him about it and make sure he set the dist camshaft retard setting.
Let us know how it goes.

You need to find out if it is a dead miss on one cylinder or other.
A cylinder miss will show up on a scanner.
Also ask him about it and make sure he set the dist camshaft retard setting.
Let us know how it goes.

He said the scanner showed #3 misfiring. I hooked a spark tester to #3 and there is blue spark. I think it looks normal but I am not an expert. I will replace plugs tonight and bring it back in the morning. I replaced the rotor and cap with no change in performance. What is or how do you set the dist camshaft retard setting? I would like to know what this is before I ask him about it in the morning. Thanks

It is the same as what setting timing used to be.
You have to have a scanner that will read it and adjust/set it by turning the dist.
It should read as close to 0 degrees - or + as you can get it.
It centers the rotor to fir dead on with the plug wire terminals.

It centers the rotor to fir dead on with the plug wire terminals.

But don't you have to first make sure cylinder #1 is at TDC, then turn the rotor to the 6 stamped on it (6 cylinder) before you do any other adjustments? This is what I am assuming they did not do correctly, as the Blazer was running smooth as a top when I broght it in. Thanks for the reply.

Yes that is the proper way to set the dist on put back together.
Then after you start the engine and get it going you need to put it on a scanner and fine tune the dist adjustment.