: 1996 Fleetwood LT1. Misfire will not go away. Please help.

11-30-10, 12:18 PM
I have a 1996 Fleetwood with the LT1 with 50,000 original miles. It has a miss with the check engine light on and the only code that comes up is "multiple/random misfire". I replaced all the plugs and wires with the best quality I could buy (and oem plugs), but nothing changed at all. It has been at the mechanic now for 3 days and he determined a slight leak on the water pump weep hole, and said we should replace the water pump and the cap and rotor on the optispark distributor. When he opened the opti, it actually had moisture (red coolant) in it, so he thought we had solved the problem. He just called me to say it is back together now but the miss has not changed and is still there. He wants to check the injectors now and do a compression test. I am wondering if he should have replaced the whole distributor rather than just the cap and rotor. But is there a sure way to determine if the distributor is the actual cause? Perhaps it is the coil? :confused: I have seen lots of things on the Internet about these engines developing a miss, and I have yet to see a post where someone found the problem and fixed it. If any of you knows, I would sure appreciate some advice. Thanks very much.

11-30-10, 12:29 PM
if anyone knows, it'll be Jim (thefleetwoodguy) he knows everything about these cars. :D

11-30-10, 02:12 PM
well I wish I knew it all
but a friend down in boston had that same issue
with his 96, he was about to throw a match into it
he replaced everything! and, kept getting the random missfire code
if I remember correctly they had to reflash the computer
whatever that means, I will contact him and try to
get more info on what exactly cleared it up for him~~~~~

11-30-10, 02:40 PM
Did he replace the complete opti or just the cap and rotor?

Other causes:
- vacuum harness on the opti
- coil
- coil wiring

11-30-10, 04:21 PM
what I have done to find what cylinder was missing was this... I took of all 8 of the spring clips holding the plugs on the injectors... Then start the motor and take one injector plug off at a time until you find one that does nothing when you take it off...so you don't miss under stand me , if you feel the motor skip when you take it off , put it back on... Then if you find the cylinder, check the plug and wire... I like to take a long plug wire and loop it from the plug to the cap.. just to check its not that... The you can check the coil in the injector with a ohm meter... compare the reading with the other injectors.. should be about 12-14 ohms.. I'm guessing...I have seen injectors short out and have a lower number or open and get no reading.. both are bad...

12-08-10, 02:12 PM
Thank you all very much for the help. My mechanic said there had been coolant inside the cap and rotor and it still needed to be replaced and the water pump too, so that job was not really wasted, even though the miss never changed. The injectors all tested fine (ohm meter), but I think he did the test that was described above of checking each injector by pulling the plug. It was cylinder 8. It definitely had great spark, so he did a compression test, and great compression. So the only thing left was no fuel (or no air!). He took the injector out and replaced it, and the miss completely disappeared. So, it was a fuel injector. With such low miles, it was an unlikely thing to go bad. Thank you guys. Problem solved!!!

12-08-10, 02:27 PM
Glad your Fleetwood is in working order again. Any photos? 50k original miles... sure must be nice. :)

12-21-10, 06:24 PM
Glad your Fleetwood is in working order again. Any photos? 50k original miles... sure must be nice. :)

Hi I am sorry I never saw your response until I looked again today. I actually have two '96 Fleetwood Broughams. The one that had the injector go bad has not been photographed very well, but I will sometime and send you one (it is gold aka "Frost Beige"). It is a really special car, but I actually like the older Cadillacs the best. :-)