Hello from a recent member. I have been lurking and getting ideas, but now I've got an issue I could use a hand with.

I can't afford to have somebody competent look at this, so I figure I'll give it a shot. The problem is this: when I go up slight hills and maintain speed, anwhere from say 40-60 mph, I get this hesitation. There is a faint tunk, followed by a vaahroom, and this is repeated perhaps 2 times every second. I feel the car stutter when this happens. Gas mileage has been horrible since I got the car. That was three years ago at about 106k. I get about 250 miles per tank. Worse lately. I have a lead foot, but I wouldn't have thought it would be this bad. I don't throw any lights. I hope it isn't the tranny. Edit: Is this that stupid surging thing that others have mentioned?

I have already tried fuel injector cleaner. I did my plugs maybe 10,000 miles ago with splitfire plugs from Wal-mart. They had never been done I don't believe. They look pretty much normal for wear as far as I can tell. No black gunk or anything.

I didn't do the wires at that time. I did the PCV valve a few thoursand miles ago. I just did the air filter. Did the fuel filter when I bought the car (18k miles ago), I do my oil changes every 3,000 miles. I drive 1 mile back and forth to work, plus stop and go driving rarely over 15 minutes. I drive for 1.5 hrs on the highway each way perhaps twice a month when I go up to the twin cities.

The ignition coils are also original. I took them off and cleaned the corrosion off the plate, but that didn't help. I have not checked them with a meter yet, as I just discoered that on the site today. Is this worth checking?

Basically, I intend to do the following over the next few months as money allows (I'm a broke medical student). I will do new plugs and wires, the oxygen sensor, may do a new fuel filter, The question is, where do I start? I was thinking the first step is definitely to check the ignition coils, because that is free to do. Next, I would probably do the oxygen sensor.just because my mileage has been so bad, and I wonder if that might be causing this problem as well(getting a little rich?)..

I'd appreciate any insight into what might be going on and cheap ways to assess it.

Checked the coilpacks as described here. They check out OK.

Definitely replace the plug wires. I had the same thing about a year ago with 52K miles on my car and that solved it. Since you already replaced the plugs 10K ago, try just wires only and see if that helps before spending more money. Decent wires cost around $50. Original AC-delco work well enough. I heard Bosch isn't good. O2 might help gas mileage, but wires should fix hesitation.

I agree completely. This is most likely ignition related. Your O2 may be shot (likely is) but it won't cause this problem.

You guys are the absolute best. I took your advice and did the wires. I got the $30 Autolite Professional Series. I drove all over town and took it to several areas where I almost always had the problem. I got no sympstoms at all. I'll probably do the oxygen sensor next month. Thanks.

I did notice something else while I was under the hood though. The hose in the picture is shot:


Tried to get a replacement off a junkyard, but they weren't willing to part with it. I'm not even sure what it does. Seems to be involved with the fuel delivery system in some way. Anybody know what it is?

I also noticed that I need to clean my engine compartment.

It is the vacuum supply hose to the fuel pressure regulator. When vacuum is present, it lowers fuel pressure. You can get vacuum hose at about 14 cents a foot at Autozone.

Thanks. I think it is 5/32. Would that explain the god-awful gas mileage?

Yes, it could.