I own a 99 Avenger, 2.5 V6. Currently I have a rough idle issue. No power when accelerating. Check engine light blinks, mostly when climbing hills. Had one code, P0305 - cylinder 5 misfire detected. This code did not show up the last time it was test driven.

I have replaced the spark plugs, wires, distributor cap and rotor. I have removed and cleaned all sensors on the intake, plemun gasket was replaced. All vacuum hoses have been checked, brake booster hose replaced. I have not tried Seafoam yet.

Need help! Any suggestions?

 

were the plug wells dry ? full of oil ?
seafoam can help clean the intake tract
The fuel injectors can cause misfires as well

 

There was some oil in the plug wells, enough to cover part of the plug. What does the oil mean?

I will try Seafoam tomorrow.

 

Oil in the plug wells are leaking O rings and valve cover gasket , This can cause misfires as well The oil builds up and the wires can ground out to the oil

 

Thanks bad venge, I will replace the valve cover gaskets and tube seals. I appreciate the info.

 

Me again. Replaced valve cover gaskets and tube seals. Used Seafoam today. Some improvement with idle, small shake when in park. Test drove, ran good...and after 10 minutes, CEL is blinking, new code is P0301, cylinder #1 misfire. CEL blinked several times during drive, at different times, more when driving up-hill. Power loss.

Car has 97K on it. I am also going to try replacing the fuel filter.

Any suggestions will be appreciated. Thank you.

 

Did you run seafoam THRU the gas ? sounds like it's traveling 5/1 so I'd suspect bad gas /fuel injector / fuel filter

 

Yes. Ran Seafoam through a vacuum line (1/3 pint) and added remainder to the gas. I will replace the fuel filter this Saturday. Is there any way to test fuel injectors?

 

since the misfire moved I'm thinking it's not the injector , if it was the same then I'd suspect it but since it moved I'm trhinking fuel pressure/filter issue

 

I took some time away from this project...

So far I have replaced fuel pump, fuel filter, spark plugs and wires, dist cap and rotor, ran Seafoam thru vac line and added to gas tank.

At this time, car will start but engine stumbles and stalls. Codes show multiple misfires. Local mechanic said try fuel pump first, which is now new, but it may be the distributor.

Have not replaced crankshaft sensor yet. Any ideas?