surge / lack of power

[gbeeley]

Hi all,

Just thought I'd run this by you guys and see if anyone has any suggestions. My '91 (221K miles) has developed a problem where after about 45 minutes of 'heavy' driving (up hills, etc., as in the mountains) it will start to lose power and rhythmically surge and sag, about once per second or two. Letting it sit off for 5 or 10 minutes makes the problem go away, but it will come back eventually.

I am suspecting a weak fuel pump. I didn't have the gear to do a pressure test, but did get out (with engine idling) and listen down by the gas tank after the problem developed, and could hear the pump surging dramatically (with a slightly rough idle). Also during the 2-sec prime with engine off key on, the pump would sound very noisy, though after letting the engine sit for a few minutes, it would resume its normal clean "hum" or "whir".

I think it's the pump, but am not 100% sure, so wanted to get your opinions... Thanks!!

- GB

[HotZ28]

It could be a clogged sock on the fuel pump pickup. How long has it been since you changed the fuel filter?

[gbeeley]

Put a new fuel filter on it just a few weeks ago (there had been some suspicion of fuel flow issues before).

So I take it that at higher fuel flow rates, the pump may be overheating due to a restricted screen?

I see on rockauto that the sock is only like 12 bucks. But is it worth it to go through the labor of removing the tank, pump, sender assembly, etc., and only replace the screen? (unfortunately this time around I'm not in a position to do the job myself).

Thanks, HotZ28!

- GB

[HotZ28]

If you go through the expense of pulling the tank, I would replace the fuel pump also! Before you do that, do a pressure test, if it checks ok, then put two or three bottles of Heet in the gas. You could have some water in the gas.

[LeSabre97mint]

Originally Posted by gbeeley

Hi all,

Just thought I'd run this by you guys and see if anyone has any suggestions. My '91 (221K miles) has developed a problem where after about 45 minutes of 'heavy' driving (up hills, etc., as in the mountains) it will start to lose power and rhythmically surge and sag, about once per second or two. Letting it sit off for 5 or 10 minutes makes the problem go away, but it will come back eventually.

I am suspecting a weak fuel pump. I didn't have the gear to do a pressure test, but did get out (with engine idling) and listen down by the gas tank after the problem developed, and could hear the pump surging dramatically (with a slightly rough idle). Also during the 2-sec prime with engine off key on, the pump would sound very noisy, though after letting the engine sit for a few minutes, it would resume its normal clean "hum" or "whir".

I think it's the pump, but am not 100% sure, so wanted to get your opinions... Thanks!!

- GB

Rent a fuel PSI gauage from AutoZone. Check the fuel PSI. Keep the gauage conected and check the fuel PSI when the engine is running poorly.

I've heard that the electrical conection on these pumps can get bad by the tank. I tried to pull the tank on my 93 Taurus but the bolts were rusted solid.

Dan