I have a few things to check on my '88 3.2L but appreciate any other input.
While on the highway heading home, cruising at about 70mph (just a bit over 3k rpm), while going over some minor bumps / dips in the pavement the engine cut out briefly. Tach dropped like the engine shut off and i felt the loss of power. Lasted only a brief moment, then power came right back and continued cruising no problem. Further on down the road while changing lanes, as soon as the front wheel hit the group of reflectors dividing the lanes the engine cut out completely and stalled. I coasted onto the shoulder to a stop and restarted. Engine cranked over and started back up without much trouble. The cut out of the bumps happened a few other times and it stalled a total of two times during the rest of the trip home. All of this occurred while going over dips or with excessive vibration from the road.
Interestingly enough i experienced the cutout briefly on this same exact stretch of road a few months back during the last 200 mile round trip i made. I could not get it to replicate and did not think much else of it.
Other details;
-70 degree ambient
-Dry conditions; car made it all the way to LA in the morning with wet roads, but i am certain the car was totally dry at this point.
-3/4 tank of gas
-All vacuum hoses, intake gaskets..etc done a few months back along with speed / ref sensors. Car runs great otherwise.
-CHT sensor is the 2-wire type; i did not replace it.
-Fuel filter is less than a year old.
-Injectors are rebuilt from 3rd party supplier
-New fuel pressure regulator
-DME relay is new
-Cap and rotor have less than 3-4k miles on them.
-Ignition wires have 10k miles
-Most of the grounds on the car have been cleaned over the past year, all battery connections clean and tight also
Here is what i was thinking...
1) To me it almost felt like a fuel cut is happening which makes me suspect the fuel pump. The pump is quiet, but perhaps during extended running (1.5+ hours) on the highway its getting weak. The pump is original as far as i know with 165k miles on it.
Unfortunately i filled up after the first time it stalled, so i have like 20 gallons in the tank to siphon out. The plan is to replace the pump, tank screen and the pump suction hose which i am sure is dry rotted. I wanted to do this anyhow eventually so i figured a good place to start.
2) DME solder joints; perhaps bad solder joints in the DME, after driving an hour or so the DME builds up enough heat combined with road vibration to cause an issue. I plan to send the DME somewhere for testing / inspection aswell for peace of mind. I would be more inclined to think though if it were a DME issue than the car would just flat out stall rather than feel like it cuts out? I plan to reinstall the DME on some rubber mounts to help absorb vibration; maybe some bubble wrap
. Ill pull the DME out when i get a chance and give it a once over for cracked joints.
3) Ignition switch is original i believe also. Perhaps the contacts are getting weak? I dont think this is it because i would suspect the problem to happen all the time. Not just after an hour or so of driving.