I have a 95, F150, 5.8L, and I cannot get it to idle right. When the truck is in park it will lobe from 1300 rpm to 800 rpm. In drive it will lobe from 1000 rpm to 500 rpm or below. I recently rebuilt it and put a different cam in. The cam has 114 lobe sep so it creates the right amount of vaccum. There is no EGR no O2 sensors no cats no emissions what so ever. I also put in 21 pound fuel injectors instead of the stock 19. I've checked the IAC and fuel pressure regulator and they're both functional. The feul filter and air filter are new.

Also does anyone no where I can get a vaccum hose diagram.

 

Why no O2s? is it MAF or MAP?
MAP does not like cam changes and if MAF the EEC is caled for 19s using stock MAF.
And no O2s will force the EEC to run in open loop.

 

There were no cats or O2's on the truck when I bought it so I haven't bothered to put any on. I dont know if its MAF or MAP. My haynes manual says MAP and TP. How can I make sure thats what it is. I am planning on a custom burned chip to make up for all the missing parts and sensors.

I have also heard of O2 simulators, will this help with the open loop problem or is the EGR not being there going to cause that as well.

 

http://www.thepartsbin.com/repsite/ford~map_sensor~reparts.html
map

http://www.aa1car.com/library/maf_sensor_ford.gif
MAF

And you might wana put the O2s back unless your going to map out the whole fuel curve for part throttle and WOT.

 

Will putting the O2's fix this or do I have to put the whole EGR system back on.

 

I would say it will help as for the EGR system may want to wait until
a few others chim.

there usually on in the afternoon.

 

both of these components missing is going to screw things up. The computer will be looking for input from both sensors, and not get it. Like Dom said, it'll go into open loop or limp home mode, which isn't good.

You can get a cheap EGR simulator and an O2 eliminator, both are just a resistor that connects across the leads from those sensors to make the computer think there's a signal. Neither one work very well - the computer relies on good info from both sensors to adjust fuel/air mix, and a static signal doesn't do you much good.

If you plan to go with a custom tuned chip, this would be the time to buck up and do it right.

 

You absolutely need the oxygen sensor. The computer is just guessing at how much fuel to give the engine. There isn't any oxygen sensor simulator that will fix that problem. The EGR will help the running and driveability so it would be best to put that back on, but all the other emissions stuff isn't needed. '95 5.8 is MAP, and as was stated they don't like cam changes. The MAP sensor should be bolted to the firewall and has a vacuum hose running from it to the intake manifold. The vacuum hose diagram is under the hood, usually on the air box.

 

Where can I find EGR simulater, who sells them?

 

You don't need an oxygen sensor simulator, you need an oxygen sensor. The simulators are used on OBDII vehicles to eliminate the rear oxygen sensor but your truck doesn't have the rear one, it has the front one only that you NEED to keep.