94 gsr bogging and backfiring while accelerating/grey sludge in coolant reservoir
 

I have a 1994 Integra GSR that has been randomly bogging out and backfiring when accelerating. I have replaced the plugs and wires, and all cylinders are getting spark. Also have replaced the fuel filter and issue still occurs. I looked in the coolant overflow and noticed a grey colored sludge which makes me thing blown head gasket. Any ideas on what could be causing this bogging problem?

Re: 94 gsr bogging and backfiring while accelerating/grey sludge in coolant reservoir
 

Compression check it, but the last B series I saw with that charcoal colored stuff was a blown head gasket. It was blown between the combustion chamber and the water jacket on cylinder 2 or 3(cant remember which) and pushing the exhaust gas back into the cooling system and into the overflow.

That engine also had other "issues"... so it was disassembled and I used what I needed and scrapped the rest.

Re: 94 gsr bogging and backfiring while accelerating/grey sludge in coolant reservoir
 

Sounds like a head gasket. The fact that you have any kind of non-coolant in your coolant means there is something wrong that needs to be fixed, and there is usually only one place on your engine where different fluids can mix together unless you have a broken block or cracked head. That place is the head to block interface, which is sealed by the head gasket......