Could the egr sensor be the cause?

 

There is no EGR sensor. Could the EGR VALVE be hanging open causing a vacuum leak? Yes.

TESTING THE EGR VALVE FOR 87-90 4.0 ENGINE
Valve Opening Test
1) With engine at normal operating temperature and at idle,
rapidly open and close throttle. Open throttle sufficiently to obtain
at least 1500 RPM. Movement should be noticed in EGR diaphragm.
2) If diaphragm does not move, probable causes are: faulty
vacuum signal to EGR, defective EGR diaphragm or defective
backpressure sensor diaphragm (if equipped), or leaks in vacuum lines
or connections.
Valve Closing Test
1) With engine at normal operating temperature and at idle,
manually depress EGR valve diaphragm. RPM should immediately drop,
indicating that EGR valve is not leaking and had been properly cutting
off exhaust gas flow at idle.
2) If there is no change in RPM and engine is idling
properly, exhaust gases are not reaching combustion chamber. Check for
plugged passage between EGR valve and intake manifold.
3) If engine idles poorly and RPM is not greatly affected by
manually moving diaphragm up, EGR valve is not closing off exhaust gas
flow. Check for carbon between pintle, leaking EGR valve gasket or bad
EGR valve.
***************

 

Sweet thanks! I will try that

 

When I changed my exhaust manifold i didnt have the intake manifold seated right the first time and it had a serious air leak that almost blew the engine when i started it. I would make sure that intake manifold is fully seating and not leaking at all

 

Check your o2 sensors connections, I was having similar rmp problems

 

The EGR can also hang open a bit. Reach into it with your fingertips and pull the diaphragm back toward you. It should stall or nearly stall.

 

Took out the egr valve sprayed it with wd40 put it back and it seemed to be working much better. Should this fix the valve or do u suggest buying a new one. And could the egr really be causing all these issues. I only drove it for a couple blocks as it was raining all day here in LA and i didnt wanna risk getting stranded lol

 

Yes, it could cause rough idle/low idle issues. It could have been as simple as a piece of crud not allowing the EGR pintle to seat.Time will tell.

 

jkshavoc,
What's the word, are you good to go?