Engine Sputter

[clyde2point0]

Hi Guys

 

I'm having a problem with my '91 Eliminator 4.0L and I could use your help. First off, I'm not "shade tree" mechanic. I know how to do basic stuff (change the oil, change the spark plugs and wires, change the distributor cap and rotor, etc.), but am useless when it comes to the major stuff so that's why I need your input.

 

A couple of months ago I had to fill up at a "no name" gas station and began having problems associated with "bad gas". I had the fuel filter replaced and the fuel system cleaned and that problem went away. However, since then at ever increasing intervals I have a problem with the engine sputtering under acceleration. When I start from a dead stop I can accelerate through first gear without any problem, but after that as soon as the tach approaches 1500, it will sputter. It does this all the way through 5th gear, but the truck runs fine at idle. One other thing that has been happening on occasion is when I start the truck up, I have to keep it reved up for about ten to twenty seconds to keep it from dying.

 

I had a similar problem with an old Cutlass. If I shut it off and restarted it in less than twenty minutes or so, it would sputter and I had to keep it reved up for a couple of minutes or so or risk it dying while I was trying to pull into traffic. The culprit then was a fuel pump going out. Could it be the fuel pump be causing the problem or do you think it's another culprit? I want to get your input before I take it to a mechanic because some of them see an old truck like mine and instantly think "CASH COW".

 

Thanks in advance for your help!!!

[FlexdXJ]

My mom got bad gas in her 94 XJ and it ended up frying the ECU. I was young when it happened, so i don't know what her symptoms were.

[clyde2point0]

Well my initial diagnosis was correct, it was the fuel pump. The pressure reading was 6 when it should have been 31. Made a BIG difference in performance. I think it had been gradually going out so I didn't notice the drop in performance, I just thought it was the normal drop due to aging. I figure only having to replace a fuel pump once in twenty years isn't too bad!!!