I have a 1996 Olds Cutlass supreme. It had a ticking noise, ran a little rough at idel (barely rough, fine on acceleration) I started to restore this car with a tune-up first. Premium wires, acdelco plugs, and an ignition module. Nothing changed, but it did need the tune-up. The codes from the computer were:
Random Cylinder misfire
EGR insufficient flow
I checked the egr (Linear or Digital type, whatever you prefer to call it) and it seemed that the pintle was leaky. I used intake cleaner while turning and working the pintle, I applied shop air to it and it was sealing at this point. I applied shop air to the exhaust intake side where the tube goes to the exhaust, it was very free, also the passage to the intake was free. I do know that the differential pressure feedback exhuast (DPFE) sensor is in the EGR assembly, because the EGR has 5 terminals, 2 for solenoid, 3 for the sensor. Although the EGR would never be commanded to open at idle, I thought that this might be the reason for the random misfire, but when I checked freeze-frame data, the misfire happened at 2000 rpm's, and vehicle speed was 0! So it happened when the EGR would never be commanded! OH N0ES!!!
But anyways, I had replaced the ball joints and outer tie rod ends today after work, and when I went to put the vehicle on the alignment rack, the vehicle ran EXTREMEL rough! It would try to stay alive every ten seconds by revving up, then back to low RPMS (most-likely mis-firing) so I opened the hood, and hit the MAF a few times with a wrench. I didn't die, so a faulty MAF wasn't the problem. Then the car magically ran fine again ( fine being the idle that has a very small hint of roughness. After I aligned the beast (set the toe, and let'er go!) I took it out of the shop, checked the codes again, this time it was the same misfire, random, and there was a code with no explanation for it, I looked it up on the internet and others have said it was an EGR code. So maybe back to square one?
On the test drive the car ran great! It was a little rougher at stop lights. I went to the BK and bought a chicken sandwhich. I ate the sandwhich and I was thankful. Really, I had been working all day and missed lunch, Lexus stays busy! So anyways, after I ate, the car would hesitate trying to accelerate from a stop, huge misfires, but then I would punch it and she would rev-up great! So I am guessing the fuel pump is not a problem!
It is a 3.1 sequential inject ( of course) with 186,000!!!
These are the only photo's I have of the car right now, so not very helpful.. The ES is mine too by the way! My only transportation too....