94 Civic VX

I am the original owner of a 1994 Honda Civic VX. It has 223,000 miles on it and still looks like the day I bought it new. It has received synthetic oil since its first oil change. I am the type that checks my mileage after every tank. This car has ALWAYS gotten between 37 and 39 mpg. About two months ago the check engine light came on. The EGR valve was replaced. Now I have two big problems. This car never had much power, but now it could not out accelerate a Yugo! Worse yet, the mileage has dropped to 32-33 mpg. I have checked for leaks at the hoses and the base of the valve. No leaks anywhere. The dealer replacement EGR valve cost over $400. The one I got cost $250. Is there that much of a difference between OEM and replacement parts? Other than replacing this valve, is there anything else I can check.

Well, there’s a lot of miles on your vehicle. And a lot of things can happen to an engine over this mileage.

Compression could be dropping off causing a lack off performance and a reduction in fuel mileage. Catalytic converter could be plugging up resulting in the same.

What you might want to do is take it somewhere and have them do a compression test, both dry and wet. This will indicate if the engine is just plain worn out. Also have them do a back-pressure test. this will indicate if there’s a problem with the cat.


Thanks Tester. I will check both today.

While both of those possiblities are quite relevant, it sounds like your MPG was fine up till your EGR repair. Your compression isn’t going to disappear overnight from an EGR problem. Also, you can have someone test the backpressure on your convertor.

If everything was fine before your EGR was replaced, you should first question the parts replaced and in the area of the repair.

My '95 VX has 207,000 miles on it and I average 42mpg still.

For openers, disconnect the EGR for a day or two and see if things improve. It won’t hurt anything. It should ONLY open when you are at a steady state cruising speed, NEVER at idle or when accelerating.

Many older Hondas required periodic valve adjustments. Does yours?

I agree with pj1071 . . . a Civic with 207,000 miles with regular oil changes (synthetic oil too!) wouldn’t be worn-out. My Accord has 440,000 and isn’t worn-out. But the big thing here is the timing of the performance drop-off/mpg drop . . . if indeed it was right after the part change (EGR) then work backwards. Change the EGR again with a salvage yard part for a few bucks, see if it makes a difference. Parts can be bad right out of the box. If the EGR is OK, look for something the mechanic did while changing the part . . . like maybe bumping the distributor? . . . knocking off a hose or wire? blocking off the air intake tube? anything is possible. Tester suggested a blocked exhaust, which is also a good possibility. This drop in mpg is significant and looks related to the recent work done. Rocketman