Intermittent hesitation around 2-3k rpm

rideonsurf

I have had my wagon for close to a year now and when I first got her she ran unreal, no hiccups or hesitation whatsoever. Then I added a quart of Seafoam to the tank like I've done twice a year to previous cars I've owned and I swear if it didn't make things worse. (maybe it was coincidence) Now I have this really bad hesitation right around 2-3k rpm mainly in 2nd and 3rd gear. It's a 6spd manual 4WD and it runs relatively smooth as long as I keep the RPM's up above 3k but it stumbles like crazy like it's not getting enough gas under 3k. It also happens in 4th and 5th gear but not nearly as often. I've noticed that it also seems worse when the humidity is high. However it gets better if I can get the car over 60mph for 30 sec or so- after that it's smooth again. So far I have replaced all the plugs/wires, cap/rotor, fuel filter and I even had a fuel sytem clean done to it which seemed to do the trick until I had to fill-up again and right back to square one. My brother seems to think it could be bad injector(s) or throttle position sensor. I also added another quart of Seafoam about a month ago to a full tank and it ran incredibly well til I filled up. I'm stumped, can someone please tell me what to try next?

Jaker

Could you have gummed up your O2 sensor with all the crap that was cleaned out by the seafoam? I've had a bad hesitation in that RPM range before, and if I floored it, it would clean up. If I tried to cruise at part throttle, it would hesitate like crazy. I had no codes for the O2 sensor, but I changed it anyways. The problem was gone.

rideonsurf

As it turns out I think it was a bad ground to the fuel relay. For the past couple of months I've noticed this little relay just kinda dangling right above my hood release lever. I looked up underneath and sure enough the bolt that holds it up there was gone so I put it back in place with a new one and VIOLA! It purrs like a kitten! I had no idea that that would have anything to do with it but that was definitely the culprit. Maybe it wasn't but the damn thing is running like a top and thats the only thing that I messed with. I can't wait to wake up and drive it again in the morning!