Ignition problems

[Laurent]

Hi, I have a problem of irregular minimum with my 5.7 hemi.

At minimum the car tremble a little the car and the hand of the tachometer oscillates a little.

I have changed an ignition coil and all the spar plugs (mopar parts) but the problem seems to have diminished a little but often comes back again.
apart from spark plugs and ignition coils, what can I check?

 

[MADDOG]

Clean the intake manifold throttle body.

 

[Laurent]

just cleaned throttle body, nothing has changed. intake manifold how do I clean it? just disassemble? do I have to change gaskets?

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[Laurent]

And throttle body wasn't dirty

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[indept]

Is you check engine light on? Have you checked for OBDII codes? It can store codes without turning the engine light on and it may help you find the problem.

 

[RodeoRam]

Camshaft and crankshaft position sensors? I'm just throwing out this possibility for those of you who know more about it.

When mine started going out on my 2001 5.9L, the tach fluctuated thousands of RPMs without the actual engine RPMs changing. While I was driving it to the mechanic, it started sputtering, bucking, and dying at interstate speeds every few miles. I guess the computer was trying to adjust to the faulty sensor data it was getting. I was lucky to get there in one piece before they completely died.

IF this is your problem, it won't get better. It'll get worse. Like indept said, read your codes, and get it checked out before it leaves you stranded.

 

[Laurent]

Now i can't read with attention (my english is not very well).
I had read a lot of cides with the diablo, they are of ignition p0300 and the second one is p0430.

I cleaned the first one and after 10 days (indicative) the second one is p0430

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[Laurent]

maybe I found the problem. the old owner must have used 5w40 oil, while the hemi engine asks for 5w20

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[RodeoRam]

I'd be surprised if that were the problem, Laurent. A few people here are running 10W40 in their 5.7 engines with no problems. If the oil were too heavy for the oil pump, I'd guess the engine would overheat and seize up instead of a little trembling and tach oscillation.

Researching your OBDII codes, I think it could be a catalytic converter or O2 sensor issue. Those are the causes that are common to those codes. Here are some links for you to research for yourself.

https://www.obd-codes.com/p0300

https://www.obd-codes.com/p0430

If your O2 sensor feeds bad data to the computer, it can affect the fuel mixture. If it is burning rich, then some unburned fuel can get to the cat con which could melt the internals and cause it to partially or fully clog raising the exhaust pressure.

Did you examine the spark plugs you removed for any oil or burning rich/lean?

 

[Laurent]

I do not think they are the catalitic converters, the ram has only 75,000 miles. spark plugs are all new; I could try to clean the o2 sensors

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[Laurent]

also because a ignitio coil was broken, maybe a o2 sensor is dirty

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