Have a problem

My 95 Formula is acting up. About every third time I drive it, the engine starts to act like it's starving for fuel: the idle gets real choppy, and it's hard to accelerate. A new coil and ignition module have not fixed the problem, and fuel pressure seems to be ok everytime I check. The fuel filter is ok, and there are no error codes in the computer. I suspect the fuel pump, but it like an $800 job to replace it. Any other ideas? This really sucks!

Check the fuel pressure while you are running the vehicle. If the fuel pressure is within normal limits then the pump may be fine but the fuel pressure regulator is probably the culprit especially if you see a significant drop when you accelerate. Change it first and see what happens, much cheaper than a fuel pump. If the problem does not improve then you will probably need to replace the fuel pump after all.

Thanks for the advice. Actually, I did check the fuel pressure the other day with a friend watching the gauge and me stepping on the gas. He said the pressure went up as the RPM's did. But since the car was not acting up at the time, I don't know what it would read when the problem is occuring. It's very intermittant. I'll try just about anything to avoid replacing the fuel pump. But with 162K miles on it, it's probably overdue.

But with 162K miles on it, it's probably overdue.

ouch

Not absolutely sure yet, but the problem seems to have been failure of the aftermarket Granatelli MAF sensor in the air intake. Apparently, a MAF error code can cause the computer to begin a temporary engine running state which includes the rough idle and lack of power. After putting the stock MAF back on, the car seems to be slowly returning to normal. I see that Granatelli now sells their MAFs for that year car with included programming to handle a cold-air intake, which the car has always had. I bet that's what made it fail: mine doesn't have that programming. Although it's out of warranty, I'm going to contact them to see if I can return it for factory repair and programming, otherwise it will be about $380 to replace it.