poor performance, overheating and no vacuum

mightybg · February 22, 2007

I have a 1991 chevy k2500, I have replaced so many things on this truck trying to get it to run right. I first thought it was a timing issue so everything from the distributor to the plugs is new. the IAC is new I checked the EGR today and it appears to be in good working order. I have new injectors rebuilt the fuel pressure regulator, new fuel filter, and replaced the knock, O2 and TPS sensors. The catalytic converter was also replaced. I hooked a gauge up to the vapor canister connection and to the connection that goes to the EGR solenoid and I am not getting any vacuum readings ~.045 "hg basically nothing. I need help before I go crazy or broke. I have checked all the vacuum lines and can't find any that would be causing that much of a leak. some body help me or steal my truck so I can get the insurance!

mightybg · March 16, 2007

timing chain warn out giving 4 degrees valve retard! and the vacuum at egr connection thing was an error in understanding, the port is above the throttle plate so it wont have any until it is off idle. but i was on the right track with vacuum, it would drop and never recover when load was on the engine. looking at articles on the internet , i thinkalot of problems can be sniffed out using vacuum readings.(if you do it correctly)

mightybg · March 27, 2007

well that's not it! after timing chain was fixed it was only about 2 degrees according to the base timing setting. truck still acting the same. i swear this is like an exhaust restriction but i already changed ou the cat and the only thing left woul dbe the muffler. has any one had a muffler go bad on them, restriction wise and still look in fair condition onthe outside? also did compression checks and got about 170psi on all cylinders.