Misifre Code/Check Engine light wont go off

[JMac101]

Hello everyone.

My names John.
I have a 2001 Dodge Caravan 2.4 Liter 4 Cylinder Minivan.

I got a check engine light back in September, and I got the codes scanned and it came back as a P0303 code which is cylinder #3 misfire. I replaced the spark plugs and wires and code came back, I then replaced the fuel injectors and the code went away and so did the check engine light. 3 days later the light came back and this time it was a cylinder #4 misfire. Since then I have replaced the following but yet still I have a check engine light:

I replaced:
Plugs, wires, coil pack, injectors, fuel rail, fuel rail wiring harness, flushed oil and filter, flushed coolant and thermostat, unclogged and cleaned the EGR, map sensor, throttle position sensor, I even went to Midas and got the Valve cover gasket as well as the spark plug tube seals replaced and yet I still have a check engine code and light. Now the code comes back as a pending P0304 but I have more power ( I can hear it and feel it ).

Is there anything I am missing? Does anyone in their experience know of something that I over looked or something else that could cause a P0304 code and light?

I asked the mechanic at midas and he says he does not see anything major wrong with the car, but he didnt really look into anything besides the cover gasket he replaced.

I asked a different mechanic and he said sometimes light comes on in error like the computer could be back. I told him that my check engine light is on steady in driver but blinks in park and he said, when the light blinks it is time to plan the funeral. Can anyone validate this?

Thanks in Advance.

 

[willix]

If you get a misfire code, then its a misfire. hardly catastrophic. Thats a lot of new parts. Perhaps the new plug or wire is faulty. Its true if the light blinks more urgent attention my be required. A misfire is a minor problem and the only consequence is it will run with a miss.

 

[JMac101]

Could my cat or oxygen sensors be bad?

 

[tomcat27]

do a compression test. sometimes leaking gaskets cause misfires also.

 

[BigNick]

Cam shaft position sensor being old and faulty can cause a misfire code. Just changed mine on my 01 Sebring. But I was getting the misfire code, and the cam shaft position sensor code (can't remember it off the top of my head)... so not sure if it's the case here... just a thought

 

[daveams]

jmac ,did you had any fuel additives in the tank?

 

[willix]

Originally Posted By: JMac101
Could my cat or oxygen sensors be bad?
The cat or o2 sensor will not cause a misfire coil/wire/plug. A new plug can be defective, so can a wire. I would think you would get a cam sensor code for cam sensor circuit problem. But I wouldn't rule that out. I would revisit the #4 plug & wire first.

 

[nthach]

What brand of coil pack was used - Mopar or aftermarket?

 

[The_Jeff]

I'd look for an IM gasket vacuum leak, IDK if they're a common problem on that motor but it should be easy enough to check. Idle it and spray something... brake cleaner, carb cleaner, WD40 (messy), unlit propane torch in the vicinity. Idle changes = found your leak.

Also if you have an EGR valve it could be hanging open and affecting that side of the intake more.

A miss at idle to me says vacuum leak b/c you have the most vacuum "tugging" at the gaskets, and the least fuel so the ratio can get off most easily. One where the light starts flashing under accelleration is often a spark problem.

 

[willix]

An air leak/vacume leak is not a misfire and won't throw a #4 misfire code. All those items mentioned will cause rough running due to too much air. None will trigger a #4 misfire code.

 

[JMac101]

yes I had used a couple STP brand fuel line cleaners and it all started when I added a bottle of it to a nearly empty tank. Could I have blown out a sensor for running too rich?

 

[JMac101]

i had the valve cover gasket and spark plug tube seals replaced as well as the oil and filter along with new plugs and wires yesterday. I used shell oil, fram filter, champion plugs and pro start wires. The coil I believe was aftermarket I got it new on ebay.

 

[JMac101]

Anyone think I should replace the EGR? I have 135,000 miles on the dash and it is original. I dont know what else to do. I pretty much ran down the list with the exception of the Oxygen sensor and the EGR valve replacements.

 

[Billbert]

Originally Posted By: tomcat27
do a compression test. sometimes leaking gaskets cause misfires also.
+1

 

[JMac101]

I can pick up a compression gauge tomorrow. Anyone know what the compression should be at or around?

 

[nthach]

Originally Posted By: JMac101
Anyone think I should replace the EGR? I have 135,000 miles on the dash and it is original. I dont know what else to do. I pretty much ran down the list with the exception of the Oxygen sensor and the EGR valve replacements.
EGR won't cause a misfire unless something is really, really, really screwed up. EGR operates ONLY when the engine is at load and at temp.