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1997 5.0l Sierra blowing cap and rotor

597 Views 5 Replies 4 Participants Last post by  Zach Smith
Hi y’all. I’m new here to posting but read the forum regularly.

I having a heck of a time with my truck blowing distributor cap and rotor. I’m going to provide as much info as I can so this may be a long post. I’m on my fourth cap and rotor in four weeks. I’ve had the truck for about three years now and it currently has 276000 miles on it. The engine is a 97 5.0l. The truck runs great and all the sudden I get a misfire. Boom, need to change the cap and rotor. This problem started about two years ago. The first time the truck died on the side of the road. Driving fine and then nothing. So I do some checking and end up changing the ignition coil. Problem solved.

About six months later, same thing. Just driving and then nothing. So this time I change the cap, rotor, new plugs and wires. Problem solved. Then three months later. Bam, I’m sitting in a parking lot idling and the truck quits. Just like that it stalls and dies. Replace cap and rotor and problem solved.

About a month and a half ago I’m driving and then guess what. She dies again. No symptoms just dies. So I have had enough with this so I decide the distributor is the problem and change it along with the cap and rotor. Truck runs awesome for six days. This time however it just starts to misfire and lose power but I can limp the girl home. Change cap and rotor and she runs great for exactly six days.

I’m frustrated beyond belief now. She did it again yesterday and I’m getting ready to put a new cap and rotor in AGAIN.

So over the last year I have researched this problem and I have found it is a very common problem with the late 90s vortec engines. GM even had a fix for it by removing the vent screens and putting foam on the AC line that runs over the distributor because of condensation.

Another common problem is the upper intake manifold had bad gaskets which caused coolant to leak. The rear seal is prone to blowing out which is right next to the distributor. I had this problem and change mine out last week. I thought that maybe this would solve my cap and rotor problem but it did not.

So in the last year I have changed out the TPS, ignition coil, new plugs and wires, new distributor, cap and rotor. My distributor timing is at 0. I took it to a shop and had them check it after I replaced the distributor. The only thing I can think of to change is the ignition module, and crankshaft sensor. I’m tired of throwing money into this great running truck and the problem not getting solved. If this is such a common problem that I have seen on forum boards and talking with people what is the solution? I have never seen the solution to the problem only the complaint.

One more thing, I am using dielectric grease in the cap. This doesn’t seem to help. I was thinking of trying to seal the cap to the distributor with RTV so I can eleminate the idea of moisture getting in the cap. Y’alls thoughts on this?

So I present the problem to you experts out there in Internet land. Please help.
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i had issues with the autozone parts. i put acdelco and its fine
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