Northstar Engines and System Technical Discussion Discussion, 94 SLS 4.6l, code P071 in Cadillac Engine Discussion; I recently got a 1994 SLS 4.6l. It ran ok for a month or so, when I began experiencing intermittant ...
I recently got a 1994 SLS 4.6l. It ran ok for a month or so, when I began experiencing intermittant rpm surges. Idle was 625-650rpms at initial start-up, and usually didn't vary much. Now, almost everytime I start it, it sounds like its idling in 650rpm range until the system monitor checking status is done. As soon asit says its ok, the idle surges to 725rpms, and then drops quickly and rises even higher 1000-1350 etc, until it will stall. I came up with code P071, P032 codes. I guess my question is, could a leaky vacuum manifold on the throttle body trigger MAP fault codes? This is my first Cadillac/N* and am hesitant to jump into testing MAP sensor, if there are other
Possible causes to test as well.
This forum is AWESOME!!!! Thanx for any advice!
Also, it seems to happen more often when when fuel is 6 galllons or less, and when temps outside are above 75°. Other codes from history P070, P032, P034, P090, P095, S044, S036. I don't know how old they are so I've cleared them, so far only P071 has returned. Thanx for any input.
Ok, been driving....the persistant codes are
Found disconnected hose? I don't see any where it would connect. Can't trace it until I put it on the lift 2morrow. Gas gauge read E, then returned to 4gal?.. Evap vacuum line maybe?
I have same issue with idle and dying. THis is after replacing starter. I replaced gaskets and cleaned intake etc, but lots of carbon build up. Runs pretty good and then will just die. I have a P095 code as well. Did you find the problem??
Well, its been a while, but I've begun t-shooting my codes/surging again. The MAP and TPS circuit's are fine, both sensors are fine. The PCM was the only thing on the circuit left, so I replaced it as well as the prom, completed the learn procedure. During the test drive, it ran great for about 2 miles, then began exhibiting the same symptoms and triggered the codes again..?
Wondering if a bad ISC could cause these symptom's?..