mach351

Can anyone give me an idea on what the problem may be. I have a 95 with a 302. A few years ago, i started to develop an engine miss on slow to medium acceleration ( particularly when it is in overdrive). It is a hard extremely noticeable miss and it continues until I reach the speed I want, and then runs fine. The miss is not evident at idle or at cruising. If I am accelerating fairly hard, I don't feel the miss. I changed the plugs, wires, rotor and distributor cap guessing that this was where the problem was. That solved the problem. About 10-15,000 miles later, it started again. I changed everything again and again the problem seemed solved. Now about 6,000 miles late it is missing and bucking again as before. I cannot believe the problem is in the wires, etc. again, but if it is there must be something else causing this to happen. Coil? I don't think it is fuel filter sinse the miss isn't evident on hard acceleration or at highway cruising speeds. However, I suppose it can be most anything.
I would certainly appreciate any ideas anyone can offer.

wde3477

Standard question - have you checked the computer for any fault codes? Does the 'check engine' light work (self-test at start?), and has it come on otherwise?

One initial thought is the throttle position sensor (TPS).
Another is an EGR system malfunction.
Computer should've picked up either of these problems.

Coil? Maybe - can check by measuring resistances of primary and secondary sides against spec, or by pulling a plug - looking for a good, solid blue spark. I would think that the problem be worst under heavy acceleration for a bad coil, but stranger things have happened.

A volt/ohm meter and a code reader go a long ways towards troubleshooting the newer, computer-controlled vehicles.

And - welcome to the site!

mach351

The check engine light does come on when the key is turned on when I start the engine. The light goes out and it does not come on at all when I am experiencing the problem. I have a friend with a code reader. I should have done that first. Hopefully, I can find the problem.
Thanks WDE3477. I appreciate your input.

svt tech

What kind of plugs,wires,cap,and rotor are you using?

wde3477

x2 on svt_tech comments, considering the problem seems solved after each replacement episode.

If you're using AutoZone-level crap, it don't last long IMHO. 'Wells' brand should be advertised as minimally-acceptable parts only for those looking to dump their vehicle to the next sucker.

svt tech

Exactly.I could have not said it better.I have been working as a Ford Tech and racing Mustangs for 20 years.I have seen it all.Those aftermarket parts,whether it be Autozone,NAPA,or any of the others just cannot compete with the original equipment.I do not understand why.I guess they will contract the lowest bidder to manufacture parts.They can make better stuff.They just do not sell it.