Took my truck into autozone since my check engine light was on. They hooked it up to the computer and it showed there was a misfire at 1 and 3. Changed all spark plugs and the 1 and 3 coils about 2 weeks ago now. The truck still shakes when stopped like and when accelerating above 35 til I get at whatever speed I am going up to it will start jerking back and fourth. It did all of this before the tune up, but then the light was on. The only difference now is no check engine light. Anyone have any ideas? Let me add that once in a great while it idles and drives with no problems, but this would be like once out of every 12 times I drive it. It is a 1997 3 door with the 5.4 engine.

 

a comp. test would be a good place to start on this one. and you may have a vac. leak some where welcome to the sight

 

I was able to replace the #1 plug and coil myself after autozone said it was #1 and #3 that had a misfire. When my nephew ran a diagnostic test on his hand help one it just showed the misfire in #3 which was after me replacing coil and plug #1, so I'm not sure it would be a hose leak. It is telling me it could have something to do with the #3 cylinder, although I could be wrong. Any thoughts on that at all? A few quick questions....

About how much does it cost for a garage to do a compression test?

About How long does it take if you do it yourself?

What exactly is it called if I go out and by the piece to test the compression myself?

I know depending on where you live prices are different and each person that does it themselves works faster or slower which is why I am asking average prices and times. I'm on disability so my nephew may have to do it like he did replacing all my spark plugs and the #3 coil.

 

it may not need the that comp. test at all but it doesn't hurt to know for sure. that test would eliminate a deeper problem. the compression tester can be rented at O'reilly or autozone and when you return it you get the money back. and then again it may have a loose connection and you need to take a look at the wiring on those connections and the overall condition of that harness. it can take as long as a day to do the job depending on the person doing the job at a shop. and it the prices very from one place to another, and with that you can call around and ask them what is their basic shop rate.

 

It might be a good idea to check the plugs that plug into the PCM for any corrosion. They did have some problems with water intrusion on some of those where water got into the plug connections at the PCM.