Well, i have done a COMPLETE tune up on the truck.. plugs, wires, coil pack, cleaned maf.. oil change..

Its still running rough.. Starts up rough in the morning, smells like its running rich.. a clicking noise comes from the exhaust?

any ideas?

has had a few CEL's all of which were #4 misfire, compression is good, die test showed no O2 in the coolant, what else could this be?

 

IAC?

have you reset the pcm? (unhook the battery for 10 min and reconnect)

 

Not since i replaced the ciol pack/ cleaned the MAF..

 

Vacuum leak is what I'd look for. Maybe also check the intake to head gaskets.

 

ok, how do i check for a vacuum leak?

 

I'd first just feel every vacuum hose. See if you can feel any cracks and if so does the engine smooth out or get worse as you bend or plug any cracks or gaps.

If you can't then try creatnig a small vacuum leak. If you already have a leak the roughness will only get worse. If you don't ,you won't notice any difference in smoothness / roughness as you create a *small* leak.

If that doesn't turn up anything try spraying ether on each joint. Including the intake to head gaskets. I'm pretty sure the engine will speed up for a moment if there is a leak.

If all those don't turn out. Try dis-connecting the MAF wire and see what happens. It'll set a light but the motor should keep on running.

Rich

 

thanks.. ill get on that prob. tomorrow.. hopefully this works.. is a vacuum leak hard to fix?

 

If it's just a hose.. then replace the hose or use some black silicon. Hopefully it's not the intake gaskets.

Rich

 

Guys, unfortunatly it is indeed a faulty intake gasket,
IMO. I have this same problem, had it for almost a year
now, and after much work and research it appears to be
the lower intake gasket.

The key is the P0304 code, #4 cylinder misfire. It seems when
the gasket fails, coolant is drawn into the #4 cylinder and
causes the misfire. It's always #4 for some reason, I think
because it's closest to the junction of the timing chain cover
and intake manifold.

I have the gasket set for mine, just waiting for enough down
time to replace. It's not a hard job, but time consuming because
of manifold removal, valve covers, etc.......

 

well, actually i dont think its a coolant leak. Havnt had a 'misfire' or a code since i changed the coil pack..

The problem infact is somewhere, for some reason, something is sending the wrong signals to the computer, which in turn is not giving the correct fuel to air mixture which is making the truck run like a$$...

Im pretty sure that its the cats being clogged or the o2 sensors, but wont know for sure untill i take it in to the shop and get a full diagnostic ran.. But i am 99% sure its not a coolant leak.

 

it very well could be that gasket the ohv had a very famous upper intake gasket failure, mine had it.

 

Ok, it isnt the intake gasket.. If there was a gasket leak, there would be O2 in the coolant from the gasses escaping. The test came up negative, which in tern means no leak, correct?

but like i said, wont know for 100% sure until i get the diagnostic done. Which wont be for a while, running low on funds and the dam thing seems to come up with a new problem ever dam day lol.. Gotta love modified vehicles.. everyhting brakes.

 

No there wouldn't be 02 in the coolant. There is an upper gasket that is also common, if you can't figure it out, take it to the shop.

 

yeah, i know its not a coolant leak also because there is no loss of coolant whatsoever.. Just loss of gas out the exhaust... Maybe a faulty injector? not really sure.. the way it starts up though, its almost like the old carb'd engines when the cylinder is flooded.. runs really rough and smells like pure fuel until it burns out all the excess gass then runs fine or better atleast.

 

Im having kinda the same problem. It seems like extra gas is going into the exhaust and turning my cat red hot. Anyone know what it could be?