F150 Lariat 1991 Nightmare

How far do you want to chase this? You could start by taking the head off and and inspecting the gasket and passages, see if you can get air to blow through them. See any good oil around the head gasket? Any leaking from the gasket, could be a sign the pressure is building up at that point if it has nowhere to go.

How does it run? Was there an oil leak from the valve cover gaskets? Any other symptoms before you took the covers off?

Rob

Sounds like a plugged up PCV valve or collapsed hose.

Al

Thanks for the reply Rob, The truck runs but at idle it is really rough/shaky. as the RPMs go up it evens out and stops shaking. The valve covers were leaking and there seemed to be a small amount of oil getting to the head but no sign of oil was on the Valves themselves. They were dry. On the other side the valves and head looked normal. No one really knows why the idle is so rough. Not sure if its timing or other. I have played with the timing by turning the distributor but no luck. Is this enjine shot? It only has 60,000 miles on it, however I am not the original owner. Who knows how he maintained it. Thanks, AD

PVC valve was removed and replaced. No luck oil is not reaching the top if the valves. Idle is really rough also... Not sure why. Thanks for your feedback. AD

Moving the distributor won't help. Set the base timing(can't recall what it is offhand) & let the EEC control the final.

I don't know what you mean by "no oil to the valves". Is it making valve/rocker/lifter noise?

The rough idle could be several things, but as another poster indicates, the deposits under the rocker cover & the idle point to a PCV/vacuum issue.

It also could be a EGR issue on the idle.

Go to Autozone and have the EEC-IV DTC codes retrieved - write down exactly what they tell you.

Run a high detergent synthetic oil with a MotorCraft or Purolator Pure One filter to help clean up & protect your engine in the mean time.

Rob

Did you do a compression check of all cylinders? What was the result?

Your probbaly going to have to pull the heads and check for clogged oil passages. Then have the heads redone at a machine shop. If they have been oil starved, you might need guides and maybe valves.

Bob

If there is no oil getting to the top of the engine on one side, it's very possible that there is no oil to the lifters either. Trying to fix the rough idle is pointless at this point. There will need to be some teardown , inspection and testing to determine where the oil flow stops. First and foremost, What is the oil pressure? Remove and inspect the rocker arms and pushrods for wear and blockage of the oil passages. If the pushrods are coked up, you may get lucky. If so, check the tops of the valves for wear. If they aren't dished or mushroomed you might get away with pushrods and rockers on that side. Cleaning out the crud is another matter. If the top of the head is sludged up, I have to wonder what is laying down in the lifter valley.