who can tell me what exactly these specific symptoms mean:
-1988 4.0L
-New intake manifold (used to leak, not any more!)
-No vacuum leaks and egr is a non-issue (disconnected)
-Starts fine but idles low/rough at first then slowly builds to high rev unless tps is unplugged
-IAC sucks really hard and causes 1500rpm rev only when tps is plugged in and then the throttle opened and closed (but returns to normal idle speed when I plug it with my hand or something)
-TPS unplugged= engine idles normal and IAC doesn't cause high rev even after throttle is opened and closed (I feel no sucking from the IAC port then)
-IAC/throttle body/intake manifold/upholstery was just cleaned and still does problem
Sooo, what causes the IAC to hold higher idle speed when the tps is plugged in? is it a faulty tps? or is the IAC controlled by cumulative sensor variables via the computer?
I am gonna take a quick little beer run while you all chime in on what my quick fix is (after this much messing with the motor I've got a high idle problem too)
BTW can anyone tell me why the motor will still (barely) run when you disconnect the vacuum hose to the MAP sensor but will instantly die when you unplug the MAP sensor harness?
-1988 4.0L
-New intake manifold (used to leak, not any more!)
-No vacuum leaks and egr is a non-issue (disconnected)
-Starts fine but idles low/rough at first then slowly builds to high rev unless tps is unplugged
-IAC sucks really hard and causes 1500rpm rev only when tps is plugged in and then the throttle opened and closed (but returns to normal idle speed when I plug it with my hand or something)
-TPS unplugged= engine idles normal and IAC doesn't cause high rev even after throttle is opened and closed (I feel no sucking from the IAC port then)
-IAC/throttle body/intake manifold/upholstery was just cleaned and still does problem
Sooo, what causes the IAC to hold higher idle speed when the tps is plugged in? is it a faulty tps? or is the IAC controlled by cumulative sensor variables via the computer?
I am gonna take a quick little beer run while you all chime in on what my quick fix is (after this much messing with the motor I've got a high idle problem too)
BTW can anyone tell me why the motor will still (barely) run when you disconnect the vacuum hose to the MAP sensor but will instantly die when you unplug the MAP sensor harness?