1988 reliant coup automatic trans. No rust outside, nice interior. Minor oil loss, very hard on gas.

Brief history of recent events. Drove the car 2000 kilometers on a long road trip. Apprx 11mpg, 250k to a tank. The car has had a chronic power problem since the day I'v owned it, 6 months ago. At highwayspeeds (100kph) the car loses power on a hill, somtimes dropping to 60kph as a sustainable speed. If I drop a gear the transmission shift's, but acceleration, and power drop below the previous gear. The entire trip was difficult for the car, and steady accelerator on a straight and level stretch usually resulted in uneven choppy combustion. The engine rarely fired smoothly. After getting it back home, I was able to start it the next day, but not after. The car sat overnight with a nearly empty tank. I havn't been able to get it started since.

All of my recent troubleshooting has pointed to fuel problems. I'v discovered a leak on the fuel line's connecting to the fuel filter outlet, on the side of the fuel lines. I'v replaced the hoses, and clamp's after discovering corroded clamp's on the old hoses. The leak is still present.I checked the fuel filter and it's not clogged. I can still blow air through it.

At this point I'm not sure what my next step is, any advice or experience anyone has would surely help.

 

First, welcome to DF, its nice to see a fellow K coupe owner here! My wife and I own an 87 Aries coupe thats in mint condition. While researching it I found out the K coupes are very rare they made less than 8000 per year. No matter what yours is a keeper!

On to your problem, it sounds like your brain box might have bit the dust, while these are hard to find they are not impossible, we have a member here named Partsandservice he works for a dodge dealer in the parts dept and was quite helpful in helping me locate parts for my 87.
Another problem might be a lack of proper fuel pressure, you said you still have a leak, I would start by checking your pressure, I dont know off hand what the proper fuel pressure should be but if you get a Haynes repair manual for the K car (they are still being printed you have to special order it, Im still waiting for mine to arrive) it will have all the info you need.

I'll be going to big show and swap meet in Rhinebeck NY in the beginning of May, let me know if your brain box is toast and if I come across one I'll pick it up for you, I'm always looking for spare parts for mine.

On a side note I dont know if Plymouth did the same as Dodge on the vin #s, but the last 5 digits tell you what # your K was on the line, ours was the 278th K car built for 87 (last 5 digits of my vin is 00278) and the first coupe made for the 87 model year.

Good luck, keep us posted on your progress.