My '03 5-speed increasingly bucks/hesitates at low throttle, and it's getting worse. Not showing any codes. Mechanic says EGR looks fine. Dealer and also local "honest/competent" mechanic say, put in fuel-system cleaner and drive it another 500+ miles and see if a warning light comes on. Great. Now I've got the system cleaner in the tank but meanwhile the problem's growing more frequent and I can't drive it at light throttle once it's warmed up--I either have to coast, or accelerate harder than I like to (so much for my average mileage, which has dropped from 54.4 to 51.4 and going down). And it's doing it on coast sometimes too, which is darn scary at highway speeds. I've seen threads about similar but not identical problems with the CVT HCHs but no clue re the 5-speed. Got 51K miles on this car. Anyone else had this problem? Thanks folks!

 

Sounds like your EGR valve needs cleaning. Check out some of the older threads. They tell you how to clean. I think you have to soak it in carb cleaner?

 

Thanks Harold. EGR valve still looks pretty clean according to my mechanic, although you're right--I should discuss this further with him--since what he considers "pretty good" might conceivably still have enough build-up up to cause trouble, maybe...

This is one of the things that's driving me batty about this problem--I've been reading the older threads and I'd been hoping it was the EGR valve--or any clear diagnosis, really. One promising thing I found just a little while ago suggests it could be the result of condensation in the gas tank from the 10% ethanol in the hot weather (and to add acetone to the tank to correct it). The problem is worse when the tank is half-empty or more, which makes me suspicious. Have you heard anything like this?

 

jojay, how are the sparkplug wires? and or the plugs for that matter. Your mechanic should be able to tell if the EGR valve is stuck open. Some of the old threads have pictures showing the procedures required to repair this problem. I read the thread not long ago. I know on my Miata the plug wire last only about 30000 kil.

 

jojay, the link is on page 2 of HCH1. [Anyone self-install their EGR valve]

 

Thanks again, Harold. I'm going to check up on all this and if I learn anything useful I'll post.

 

Sound like a dirty EGR valve to me, cleaning it couldn't hurt. Good luck.