In the past 4 months, I have had a issue with my car. I have had a miss in my car and I can’t find out whats going on with it. I have changed the plugs, coil packs, crank sensor, but it still has a miss. One or two of my plugs looked like they had fouled out, when i changed them before putting new ones in it. I am really getting frustrated with it. I also changed the fuel pump. Please someone give me some advice in what to do with my car since it is my only means of transportation with getting my son to school.
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+1 to VOLVO V70, do not post any personal information on sites like this.
Is your check engine light flashing? If it is, most auto parts store (except in the Peoples Republic of California) will read them for you for free. Post the codes here, they will look like P123. If you have plugs that look fouled they may be the source of the miss. If you have a flashing check engine light, you need to get this fixed asap, you can mess up the cat converter really quickly. If you do not have the CEL on, what symptoms lead you to having a miss? Let us know what the symptoms are and we can better help you. Mileage, maintenance history etc will help a lot. Have you changed the air filter?
You need to let us know what engine codes you have… Is the check engine light illuminated? It might not be…and if it is NOT…and you have a true engine miss, then you could have some rather serious issues.
I would read the codes if you have any…and then also do a Compression Test on the engine… Both will rapidly point you in the correct direction.
When I took it to advance it had 2 misfires then he swiped the codes. I can’t remember what the numbers was. When I take it back to have them check it doesn’t show anything. It does show I need oxygen senors and I have a vac leak. The engine light isn’t on either. The motor was replaced before I got it.
Also done a compressing test on it has well. It was fine
No code will tell you to replace an oxygen sensor or any other part.
A code only lets you know that the computer is not registering the correct values for the oxygen sensor, or other part in question.
A vacuum leak could be contributing to the miss and the O2 sensor reading being off.
If the codes are not present now, I would forget them unless they come back. Then have them read and post them all here for us to work from.
Once the engine has been started a specified number of times, and the vehicle driven a certain number of miles without the misses…the computer will erase those codes from memory.
Have the vacuum leak fixed and this may just make the problem go away for good.
If you have the results for the compression test it would also help us.
What were the numbers on a dry test and then a wet test.
techron or seafome, start simple, air filter and gas filter up to manual recommendations?
A vacuum leak can cause a symptom similar to a miss. I’d probably start there. Ask your mechanic to do a thorough check on the vacuum system, and check for possible leaks in all the vacuum operated devices too. And measure the intake manifold vacuum at idle. It should be around 20. Is it?
On newer cars “miss” is a term that has a specific meaning as far as the diagnostic codes go. It means the engine computer has fired a spark plug, and that firing should have made the crankshaft speed up a little. But the engine computer – using the crankshaft position sensor – didn’t measure the expected temporary acceleration of the crank shaft. No bang, no go.
For all that to happen the cylinder has to have good compression, a good spark, occurring at the correct time, and the correct air to fuel ratio. It seems like your mechanic has checked for most everything already, except for the air to fuel ratio. The mechanic has put an o’scope on the ignition system right? Might be time to check the fuel pressure. And fix that vacuum problem b/c it can adversely affect the fuel/air mixture too.