Car loses power on the freeway

[shadow]

Basically, what happens is, I can drive on the side streets without issue.

but after about 10 minutes on the freeway at 65 mph (4th or 5th, usually kick into 5th around here) the car starts dogging like it's out of gas

much of this started after I got a new catalytic converter like the first freeway drive afterwards (the old one was hollowed out with a hole in the side)

I've replaced the fuel pumps which were bad because there was a lean-ness issue that was killing the catalytic converter

though, much of this started after I got a new catalytic converter like the first freeway drive afterwards (the old one was hollowed out with a hole in the side)

I know my water pump has a very slow leak in it because I see wetness around it and air in the cooling system after about 90 miles or so.

no froth, no oil in the coolant, no coolant in the oil, no smoke or steam from the exhaust, so I dont think it's a head gasket issue.

Someone suggested it may be the ecu or the AFM

I think it may be the catalytic converter as all this started right after I got it, if not that, the ignition coil, but as I'm not a master mechanic (I fix computers, not cars as a career) I want to know if anyone here knows what it could be?

I'm absolutely stumped.

[SchnellerVert]

How old is the fuel filter? When you replaced the pump you should have changed the filter at the same time since you were there and they are cheap.

Old filter is probably blocked with sediment.

[shadow]

How old is the fuel filter? When you replaced the pump you should have changed the filter at the same time since you were there and they are cheap.

Old filter is probably blocked with sediment.

that was replaced with the pumps, and was why the pumps needed to be fixed, the p/o was so nice to this car..

[jlevie]

This sounds like a layer of sediment (usually mostly rust) in the tank. At the higher flow rates of highway speed driving sediment collects on the inlet screen and chokes off fuel flow. Stop the engine and it'll fall off and things will be fine until next time there's high flow.

Pull the level sensor & transfer pump and use a stick to stir the bottom of the tank. If there's a layer of sediment you've found a problem. The fix is a replacement tank, of if the tank is structurally sound it can be acid cleaned and sealed.

[shadow]

hrmm, I'm sure the guys who replaced the transfer pump would have taken notice. but all this started after I got a new catalytic converter, and there's a noticeable smell coming from the header.

the old cat was blown out, it could have been from something upstream, but when it was blown out, it could drive a considerable distance (40 mile round trip on the freeway, up steep hills too..) without dying on me.

new cat? car dies out after 10 minutes of freeway driving, or an hour (or two) of regular stop and go town driving.

I did notice my fuel pump relay and o2 sensor relays had burnt contacts, cleaned them and now my cold start works. (and there's no longer this random jerking sensation when warming up)

the fact it ran fine before I got the new cat though, wouldnt fit that profile.