When I'm driving with the car under load it will start to jump/jerk at about 2500rmps...If I put in the clutch or have the car in neutral and give it gas it idles/revs fine. I can now not go any higher than 3000rpms when driving in 4th gear or the car shakes and rattles. Also my fuel mileage is getting worse and worse as the symptons get worse. It had this problem before and was told that it was only running off three of the four cylinders and was able to be fixed by replacing the plugs, plug wires, distributor cap and rotor cap. About a month ago dad broke one of my new plug wires and replaced it with one off of my parts car which I am guessing is about 5 years old. What should I do to try and narrow down the problem or any ideas on what I should replace.

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Caleb Sarty

Black '84 SE 4 speed with blue gauge covnersion and small interior mods...Stock otherwise, but not for long.

I would start by putting a new plug wire on there, not an old one. After that, maybe the coil? They seem to go bad quick on the Fiero.

yes, sounds like an ignition problem. cap/rotor, wires, igntion module, coil

I'll definitely be replacing the wires come payday and checking the plugs (gap, condition, etc.) and give them a good cleaning...but from there should my next step be distributor or coil/mudule if it's still acting up?

BTW your rating bars each went up one

[This message has been edited by 84se-Stock (edited 02-05-2004).]

I think the coil itself is the most common ingnition problem, and probably cheaper than the cap and rotor or module, so I'd try that next if the plug wires alone don't solve the problem.

Thank you both for the info...I'll try the wires and then go from there. Wish me luck

How old is your fuel filter? If it blocked it will casue some of those same condtions.

Fuel filter is about 3 months old...had it off and checked it about a month ago. looked fine.

If you want to make an investment that will be helpful not only for this problem, but for many more in the future, buy a Helms Manual for your model. I have an '84 SE also, and I've used the manual successfully to help diagnose and correct lots of these type problems. It has step-by-step diagnostic trees that lead you to what the problem is without replacing components one by one to see if the replacement cures your ills. It's saved me much more than it cost me.

I've actually got three repair manuals for my car but they are all at home and I'm at work. I also like to get input from forum members along with the diagnosis from the manuals just to see if I get the same suggested fixes.

[This message has been edited by 84se-Stock (edited 02-05-2004).]

Have you checked the fuel pump pressure to see if the pressure is what it is supposed to be.

Well, two nights ago on my way home from work the Ferarro left me stranded in the middle of nowhere. Luckily my buddy was a few kilometres behind me and noticed me on the side of the road and picked me up. The next day I had no choice but to fix it as we were expecting 15cms of snow...which we certainly got. I went to Canadian Tire and got a set of spark plugs and went to Car Quest to get a set of plugs and a bottle of gas line antifreeze just for the hell of it. I was absolutely positive that it was a spark problem but dad kept telling me it was a fuel pressure problem. Well...after replacing the plugs (which were only a few months old in the first place but looked very abused) and replacing the wires (one of which was off my parts car and looked about 5 years old) I jumped in and fired it up. It did it's usual spit and sputter in the cold wet weather until it wramed up and then off I drove. Works great now .

Before I broke down the other night I happened to notice that an old man who I had seen almost every day driving a little red '84 fiero had it parked out by the road with a "For Sale" sign on it...nothing special and the body needs some work but I believe I'll go down and take a look at it as a project car.

One last thing...I'll never get over the looks on people's faces when they see me sitting in the trunk with a ratchet and throwing plugs and wires out of the "trunk".

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Caleb Sarty

Black '84 SE 4 speed with blue gauge conversion and small interior mods...Stock otherwise, but not for long.

I also forgot to mention that when I opened the decklid the other night to see if I could spot the problem the wind caught the decklid and split one of the support frame pieces. Next investment looks like it's going to be some fiberglass and touchup paint.

check your oxigen sensor will be a good idea

quote Originally posted by elmarkes: check your oxigen sensor will be a good idea

O2 sensor is working properly...just replaced a few months ago actually when the manifold was replaced.