I have a 1988 E3 50 with a 5.8 and I’m doing the valve covers casket and it’s totally taken apart now so I want to know what I should replace and check and do you recommend any upgrades to the air intake or throttlebody and what about the EGR system

 

You may have your engine back together by now but thought I would reply in case you don't

I have a 88 e150 with a 5.0 and when did the valve cover gaskets I changed the TPS and EGR valve because it was much easier with it apart. The EGR has a diaphragm in it and that is why i changed mine being 30 years old. While I had the plenum off I also removed the throttle body and cleaned it really good. I also cleaned the plenum. I used a combination of carb cleaner and gunk engine cleaner while at the spray car wash.

As to the throttle body, at least on the 5.0 throttle body, there are 2 vacuum lines that connect to the TB. pay close attention to those as I found one of the passages to be clogged.


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The proper way would be to remove that plug and clean the passage. I don't know if you can buy replacements though so I did the best I could with spray cleaner and a small wire.

That is probably about all you really need to do because anything else can be changed fairly easy. I used a vacuum to suck up any lose debris on top of the intake and then used a rag, brush, and cleaner to clean up the area a bit.

One more thing. If the van has sat for years then you probably have rust in your fuel tank/tanks. My 88 sat for years and had to have a new tank, sending unit, and pump. My 85 sat for years and needed a new tank and sending unit. Here is the sending unit that came out of my 85.