Ivaylonikolov

Hey guys i have 07 express with 4.3 vortex that started acting up last week - while driving down the hwy i will loose power and check engine light will be flashing . Read the code p0300 ok. On my way home it got so bad I barely made it home another code p0101. Did a fuel pressure test 45-50 psi so I removed ans repaced the fuel pump - no change. Removed the distributor and it had lots of freeplay so i put new one -no change
Truck starts right away , good oil pressure no fuel in the oil not using any coolant no smoke of the exhaust pipe.little shake on ide but revs up fine , once in gear won’t accelerate and u can hear popping in the exhaust. Timing has been verified on distributor. Starts on first revolution

mountainmanjoe

check for intake leaks

Ivaylonikolov

There is a purge valve on the upper intake manifold for the charcoal canister next to the fuel tank . Is that valve normally open or closed . Mine is open allowing vapors on . But I doubt thats the problem

mountainmanjoe

what is the mileage? Has the lower intake gasket been done?

Ivaylonikolov

250k miles. No gaskets have been replaced. Was running like a beast till last week

mountainmanjoe

then you've been lucky. Spray some water or starting fluid at the intake gasket area and monitor for changes.

Ivaylonikolov

I will try it with water i dont want it to catch on fire . Is it posible that the spider failed

mountainmanjoe

Don't worry the starting fluid is a very common trick that is used all the time. With water, you should notice the engine speed drop, and clouds of steam coming out of the tail pipe.

Yes the spider poppet valves do fail. I recall there was a TSB out there on the internet about how to upgrade the injection system, but I think it was for the older 4.3's