Cutting Out, Bad miss- Help Needed Options

[PDXBob]

Frustrated by a Bad Miss. hope the 914World Experts can help me out!

On my 1975 914 (1.8) I have had a sporadic bad miss for the last 6 to 8 months. Here are some of the details.

- it’s been doing this for at least 6-8 months. Some days doesn’t miss at all. But today it was bucking so hard I didn’t know if I’d make it home. This was the worst it’s ever been!

- When it misses it feels like it’s bucking, that is, doesn’t feel like one cylinder miss but total cut out.

- it’s worse under a load, e.g. when going up a steep hill.

- In the driveway today I could rev it up and hold it while standing still with no miss. Didn’t matter if I held it at 2,000, 3,000 revs- didn’t miss.

- not sure if fuel or electric issue. Any tests I could do to determine?

- Does it in all gears.

- The Tac does NOT fluctuate when it cuts out.

- The lights and radio do NOT flicker or stop.


Any suggestions would be greatly appreciated. Thanks in Advance!
PDXBob

[JeffBowlsby]

Our original engine bay harnesses are 50 years old now, and often are worn out. Have you inspected the condition of your FI and Ignition harnesses? Engine bay harnesses are maintenance items and must occasionally be replaced to avoid problems like you are experiencing.

With the harnesses connected and the engine idling, is there any change in the engine performance when you wiggle each branch and connection? You might also try this at night or darkened garage to observe for any visible lights in the darkness while the engine is running.

Are sections of the outer casing broken or missing exposing the wires? Are those wires brittle or the individual insulation on each wire cracked or broken?

Are any exposed wires pliable not brittle or with cracked insulation?

What is the visual condition of each of its wire terminal connections like? Remove each connection from its component and inspect each wire terminal at each connection. Are any of the wire terminals munched (bent, distorted or pushed back out of their housings), dirty, corroded or broken?


Post here if you find any questionable connection.