what could be the problem?

Question

i have a 95 chevrolet blazer the check engine light is on the code says PO303,a misfire in cylinder 3,i got a tune up,light came of for a day then came back on,code came back the same,it shakes when in park and when i am at a stand still,sometimes smell gas when i start it up,also code says rich in fluid.

Answer 1

You have a leaking fuel injector on cylinder 3. These vehicles were bad about this. I have replaced MANY. It will cause a actual misfire just like the spark plugs or wires. The fuel smell is comming from the leaking injector. I promise you this IS the problem, even without seeing it myself.

Answer 2

Someone did a poor tune up. If the light was on and the mechanic didn't read the code and fix the problem you better demand a refund or a proper fix. Mechanics charge way too much and most are not educated on the on board diagnostics of todays autos. The misfire is probably from a faulty injector or spark plug or coil. I don't know if you have plug mounted coils or not. The rich mixture is caused by the misfire. This could be a distributor problem if you have a distributor. Spark plug wires should also be checked. A tune up should fix your problem or it should be fixed at no additional charge. Better find a new mechanic.

Answer 3

I have no clue about the 95 chevrolet blazer or any American cars but if "code says rich in fluid" then I'd have to ask you when was the last time you changed the air filter (if there is such a thing on a -95 chevrolet blazer-)
Same per the 3rd pot not firing, if that's a car that has spark PLUGS then the plug might be shot, if it has injectors then it might be blocked....

Answer 4

Possibly bad spark plug wire, or bad ignition coil for that cylinder and it's mate. have the secondary ignition system checked, all the spark plug wires and the coil packs.