Solve The Mystery ......

[wirebrain]

My Festiva has been giving me a problem that I have not been able to figure out. It is a
1990 L plus, Fule injected, 5 speed, only major mod are 14 " rims and tires that put the Speedo off about 3 miles per hour and a straight through exaust. The problem was first noticed last September while running the 4 lane at 65-70 miles an hour. The car started losing power and speed dropped to where I could not keep it going 55 miles an hour in 5th gear, droping it into 4th gear and punching the pedal to the floor, it can eventualy make it back up to 65 mph, but as soon as you put it back in 5th speed starts dropping off again. When this is happening the tempurature rises on my temp gage to about half way, when it is running normaly it never makes it to the second mark. The engine sounds like it is not running normaly, possibly a miss. Then it will disapear and run normally, the temp drops back to normal and till its next trip on the interstate ,it will run fine. Plugs ,wires,thermostat , o2 sensor and airfilter have been replaced. The problem does not occure while driving at normal speeds...just sustained speeds above 65.... anyone have a clue?

thanks in advance

[fastivaca]

Fuel filter?

[FB71]

sounds right to me. loss of fuel volume/pressure, causing the engine to go lean, which makes it run hot.

[fastivaca]

Could it be the fuel pump on its way out too?

[FB71]

could be, but doubtful. I suspect the filter, or filter sock on the pump

[Pu241]

My experience with electric fuel pumps are that they run fine and fail all at once, with no indication of an impending failure.
At least nothing you would detect without some means of seeing the current flow through the pump circuit.

[hawkdoc60]

You probably have junk accumulated in the tank that is clogging it up.

[25Horseplay]

Another possibility is a clogged cat convertor.

[ohsoslow]

25's got it right (in my eyes anyway)

while reading this it screamed cat to me. have a backpressure test performed

[jglutz]

sounds right to me. loss of fuel volume/pressure, causing the engine to go lean, which makes it run hot.

Lean....Hot....definitely fuel delivery related. Maybe the fuel pressure regualtor.

[FB71]

25's got it right (in my eyes anyway)

while reading this it screamed cat to me. have a backpressure test performed

a clogged cat will not cause a hot running condition.

[edudu77]

^ You are correct sir, but a cat stuck in the fuel filter could...anyone seen fluffy?!? Sorry, couldn't resist....good luck with the fix.

Donovan

[FB71]

or a cat clogged with a fuel filter... why does Fluffy's breath smell like gasoline?

[wirebrain]

Thanks for the Sugestions, I am going to try the Fule Filter first, I don't think I have changed it since I bought her.....85,000 miles ago...lol Additional Info : Car has no Catalitic converter or muffler...but does have a section of the original double wall exaust pipe in the system...I have heard this could be a problem too. I will let you know if the Fule Filter Helps.

[Damkid]

i can't see how double walled exhaust pipe would cause your problem, i would think more towards the fuel filter