Hello all new gere.Well I bought a 2000 blazer from a sleazy dealer yesterday&as soon as I got home the service engine light came on,so I took it to a shop&they said #4had multiple misfires so they did a compression check&its reading 90psi!Well I called the dealer he said too bad!I went to the dealership they said someone must of stole our paperwork you didn't buy it here!So yeah bad day.Plus I don't think tue 4wd is working!Well the shop wants 2100 to fix it.But I've seen on ebay you can buy heads for around 300&I know talked to 2 different people that would both take 300 to remove the old heads&replace them.Or a new shop that opens Friday told me they would do the valve job for 900 so what do you guys think?Its a 2000 with 110xxx miles.Well thanks in advance!

 

300 to replace the heads is a fair price if you cant tackle the job yourself. are you sure compression is being lost in the heads? compression could also be lost between the piston and cylinder wall due to a scared cylinder wall or a broken piston ring.

 

Are you sure it's the heads? What is reading 90 pounds? All the cylinders, a few, or just one of them? I'm assuming all of them or they would have said something about a head gasket. If you want to figure out what is wrong yourself, you can use an air compressor and a piece of hose that will thread into the spark plug hole. See Below.

Unfortunately used car buying is sometimes like Russian Roulet.

Came across this and I think I'm going to post it in the garage for the future.
http://www.dietersmotorsports.com/Co...akdowntest.htm

 

Its number 4 that's reading 90psi.Ill check out the link.

 

I totaly missed that you said #4. Darn selective reading.

All the others are fine or within spec? Sounds more like just a head gasket though. It can leak between two cylinders, into the cooling system, crank case, or possibly just out into the air.