Number 4 cyl misfire code and had a map sensor circut low code
Replaced map sensor,sprk plug,plug wire,coil and had icm test 8 times in a row. Is there some kind of fuse if something shorted? There are wires that lead to the icm that the serp belt was apparently rubbing on. I can see copper on the light blue with white stripe one and on a black one with a thin white stripe. They are not touching each other and no strands r broken. It was dragging a cylinder a couple weeeks ago but then ran fine a couple days later. Now its been doing it for a week. I also tried injector cleaner first. I layed the plug on the engine and ran it and didnt see a spark.
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What engine ? 2.2 l or 2.4 L. You don't say if any codes are set. no P0303 - P0304 cylinder's 3 & 4 misfire ? or any other ? No the cam sensor wouldn't cause just two cylinders to misfire. The PCM triggers the ICM to turn on an off coil's to build up an collapse the primary voltage inducing the secondary voltage . This engine is equipped with a non-distributor ignition system called the electronic ignition (EI) system. The primary circuit of the EI system consists of the following components:
Two separate ignition coils
An electronic ignition control module (ICM)
A crankshaft position (CKP) sensor
Related connecting wires
The ignition control (IC) portion of the powertrain control module (PCM)
Important: The camshaft position (CMP) sensor is only used for a misfire detection. It is not part of the ignition system. ! How to Test the Ignition Coils GM 2 4L Quad 4
If you had code P0305, I don't know why they would have done anything to the #2 cylinder but if they have already replaced the plugs, wires and injector; here are a few more items to check:
1) Check connections from ECM. Look for any corrosions or bent/broken pins.
2) Check the fuel line pressure
3) Check the engine compression
4) And if the above are good, then you will probably have a defective ECM
misfires can be caused by plugs , HT leads and coil/s-- AND--- bad injectors, low fuel pressure. Pull the injector for no 1 and have it checked out.as t may be the injector or the wires and connections for that injector. Make sure that the HT leads are not touching each other as it may cause a misfire on the cylinder as well
having PO 304 = Misfire cylinder 4,PO 306 = Misfire cylinder 6, as I read above you have done the most. The thing that you have missed is to check whether the Catalytic Converter is faulty or not. To get an idea check whether you have a smell like rotten eggs at the end of the exhaust,you start having problems with cat and needs replacement. My advice before you go for a cat replacement is good to visit an MOT center and check your emissions and then you decide,
Possible Causes: - Improper spark plug at cylinder #1 - Insufficient compression at cylinder #1 - Incorrect fuel pressure - The injector circuit is open or shorted at cylinder #1 - Fuel injector #1 may be faulty - Intake air leak at cylinder
Possible Solutions: - Perform Injector Service - Replaced Spark Plug #1 - Replaced Injector #1 - Replaced Ignition Coil #1
Being you have a heavy gas smell I would look into the injectors. If injector #1 is over producing it can cause a misfire. Test your compression and fuel pressure.
See if you can get the codes. If it is still number 4 only (probably a P0304) it could be the fuel flow through injector 4. Try some Techron cleaner and make sure number 4 plug isn't fouled. Also get the compression checked on number 4.
If not, it could be the ignition control module assuming all other changes have been made. If you get a code it will help. A P0300 would point toward the ICM. If it is number 4 only it could still be the ICM. Expect around $150 for the module if you do it yourself. The ICM may be under the coil pack. If you are getting a P1361 and/or P1362 it could be the Cam position sensor. They are around $40 and are usually near the number one cylinder. Mine is hiding under the water pump pulley. It is a Buick with the 3.8 engine but the principal is the same.