Rep Power: 0

'02 LX Coupe AT @ 73,000 miles

Bone Stock (with the exception of Denso Iridium spark plugs changed @ 30,000 miles)

THE PROBLEM :

The engine severely shakes from 500-1200rpm. This happened out of nowhere just overnight. It has consistently been ocurring for the past 4 days. The shaking creates the sensation that the engine would shut down anytime. The shaking is not felt passing 1200rpm. Also, the ENGINE MALFUNCTION light has just turned on.

This happens all the time. It's consistent. It doesn't matter if the engine is cold or hot, it happens.

STEPS TAKEN
1) Mobil 1 Synthethic Blend 10w30 oil change - 100 miles ago

2) Honda ATF Z1 triple tranny flush - 1000 miles ago

3) Full Radiator Flush - 50 miles ago

4) Reset ECU

--->None of the four steps have created even the slightest improvement.

I'M THINKING...

1) Do I really need a tune up? The spark plugs only have 43,000 miles. I have never adjusted the valves or timing belt though.

2) Broken engine mount? I don't believe this could be possible, but who can tell me how to check the rear one?

3) Clogged fuel lines? I do drop fuel cleaners (from Lucas to Redline) every 10,000 miles. Plus I only put 87 grade Chevron or 76 gas (both Top Tiers).

4) You tell me. Have my Oxygen sensors gone down the drain?

--->Before you speak, please do not simply suggest to take it to the dealer. This is not a out-of-this-earth type of problem. I'd rather fix it myself or take it to a mechanic with some knowledge about possible sources of the problem.


Useful technical expertise is appreciated!

Thank you,
ak

PS: I am alive. Yes, I know. It has been over 8-10 months since I've posted in the TECH section. Yes, I remember you.

UPDATES
POST #4 - Cracked Denso Iridium

Thanks everybody!

 
Rep Power: 0

put the stock plugs back in. I friend of mine put some "good" plugs in his and it ran like ****. he put some everyday champions back in and it ran great. I'd try that first....

 
Rep Power: 281

i have the same problem sorta, my engine shakes when i turn it on and off, like it sends a big vibe thruout the car and i took the same steps u did and nothing happened still

 
Rep Power: 0

UPDATE:
I have removed the old spark plugs (Denso Iridium IK20) and found the #2 plug CRACKED. The tip was completely missing!!! The other end of the spark plug also came loose.

I had read on other forums that some people were having bad experiences with Iridiums (all cracking related), but ignored it. BE WARNED!!!

The tube (do not know its proper name) that connects to the spark plug was full of carbon deposits.

I'll update once I replace them with the Bosch Platinum +4 plugs and give another verdict.

Thanks bradmanuwf for the first useful reply

 
Rep Power: 0

you beat me to it, i was suppose to tell you that... but I check mine after hard driving (after race), or monthly (regular driving) no problem so far... most of us are very satisfied with the outcome after we install the denso SP... is there any SP out there that's better than the Denso Iridiums?

 
Rep Power: 340

Broken motor mount, my car use to shake like crazy till I got it replaced.

Edit: never mind just read the update

 
Rep Power: 336

i would take the car to pep boys/advance auto parts/autozone and ask them to read the code thats causing the engine light to come on. That would be the easiest way to find out whats wrong, plus its free!

 
Rep Power: 0

PROBLEM FIXED! The cracked spark plug was causing it to nearly shut down.

Question: Is my #2 cylinder semi-damaged now? I drove about 300 miles with this problem.

 
Rep Power: 0

Not necessarily. Just make sure that nothing dropped in there. You've mentioned

Did you locate and removed those missing parts from the cylinder?

 
Rep Power: 0

delete

 
Rep Power: 0

The tip of the spark plug was probably a 2mm long piece of metal. I did not locate and remove it because i don't want to open the engine.

ANOTHER QUESTION How can i remove the CARBON deposits in the cylinder? Just fuel injector cleaner?

 
Rep Power: 811

Do a compression test to be sure they're all around 135psi. I don't think any major damage was caused, although I'm not sure.I've had ngk iridium for 10k+ mies with higher compression and they're fine. Uses less voltage than stock which is a plus.

 
Rep Power: 0

simple solution: Front Side Engine Mound.....$150 CDN. it's the engine mound's problem

 
Rep Power: 0

^^ Ditto as Gear said. Do a compression check on the engine.

You may have cracked a spark plug during the install.

I have NGK Iridium IX plugs running strong.

 
Rep Power: 0

1) How do I do a compression check?

2) The plug was installed 43,000 miles ago. It was working fine until 4 days ago.

 
Rep Power: 811

compression checker is $40 at any auto place. You can diy, just unplug injectors, take out plugs, hook it up to one cylinder at a time, floor the gas, and start the car a few cranks. It should read the compression and hold the reading on the meter. They should be roughly the same for all.

 
Rep Power: 0

ohhhhhhhhhhh, thanks. Now...what if the #2 cylinder is not nearly the same?

 
Rep Power: 811

then you have problems, and the engine won't be making all the power it can. That means something inside the engine got messed up like valves, cracked chamber, scored piston....

 
Rep Power: 0

a compression test kit is about $120. take a pick if you think owning one is useful to you in the long run.