1987 "low compression" ?
 

I have a 1987 Allante, with 134,500 mi. Have had it since 1997, ith 89,000 mi . It has never overheated.

It was running really well so I went ahead and replaced the leaking master cylinder, with good results. It continued to run well for 4 days afterward, at which point it was really roufgh starting one morning. It would barely keep running. It would almost cut off. After driving it about a half mile it ran better and didn't threaten to stall. After turning it off, when I went to restart it went through the same scenario to a lesser extent, even though it was already warmed up.
Took it to the garage that has worked on it since I first got it. They said it had low compression in 3? of the back cylinders. They recommended not repairing it.
The only relevant code on the DIC was EO 41 = no cam reference signal from the ignition control module. However, the code said EO 41 History even though I first cleared the codes. It was suggested to me that the fix was to replace the distributor which includes the cam sensor, as opposed to trying to repl. only the cam sensor. This same individual, who seems "in the know' when it comes to Allantes, said he'd never seen valve or ring problems with Allantes.
Another knowledgeable friend suggested that perhaps the timing chain skipped a tooth causing the cam lobes to not be fully closed resulting in low compression on some cylinders. He said to check this out before replacing the distributor.
In looking at my repair history:
119,185 mi replaced distributor, ign. mod. p u coil
121,564 ign. coil and Deist.? moddule
128,632 Showed codes 31, 46 (Left to Right fuel difference and 49 (? 48 is EGR valve)
128,653 Replaced Distributor & fuel filter
134,500 Ran rough as I described, blew alot of smoke (only 1 time). They smoke tested it. Tested the fuel pressure regulator to 40 lbs. Pressure balance tested the compression. replaced 1 plug. Said some were only 80-90 instead of 130-150. Was told it had low compression.

really really old thread but wondering what the outcome was?

rough starting cannot be possibly connected with the ABS system UNLESS brake fluid got on sensors or electrics and did some damage.




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87 back in action
 

After sitting for most of a year, took it to another shop that works only on Cadillacs. He replaced something called the Hall effect 'switch' on the distributor, I think. Has run great ever since.
Now I have a brake problem, but that is another matter.

that may help someone in the future
thanks ..