Car: 1998 Accord EX 4 door, 4 cylinder, Automatic, ULEV

So over the weekend I did upper and lower ball joints as well as a wheel bearing. I Also replaced the flex pipe and cat to repair an exhaust leak. The day I replaced the exhaust parts I got a misfire code (the car was running ok) but figured it might be due to the exhaust leak.

Today (one day after the repair to the exhaust) on the way up a steep hill the car started running ruff and tripped the flashing CEL. It tripped a P0300, P0303 & P0304

I replaced the plugs and wires today, the cap and rotor are new a couple months ago. the plug from the #4 cyl was very black the rest looked ok. The car is still running rough.

What should I check next?

can a bad ICM or coil cause just a cyl or two to misfire.

it really sucks to have spent all this time and money just to have it run worse! PLEASE HELP!

 

Double check the firing order of the plug wires.

See my post #11 in this thread:
https://www.hondaaccordforum.com/for...d-48527/page2/

 

I am 99.9% that they are correct. I replaced one wire at a time as to not confuse them... I can double check tomorrow.

Assuming they are correct what would you check next?

 

I triple checked the wires.... I am now 100% they are correct...

 

How does your rotor and cap look?

 

Cap and rotor both look good, they were new a couple months ago...

I think I am going to try to wrangle up a compression tester today and see what I come with...

 

Well the compression test results are in and its not looking good...

cyl 1 = 210
cyl 2 = 190
cyl 3 = 210
cyl 4 = 30


How can I trouble shoot further? bad valve? rings? ect.??? I am at the point of wondering if fixing it is worth it. I am a capable back yard mechanic but have never got into motor stuff much.

the car has about 215,000. the trans was rebuilt about 2 years ago. I hate to junk it if I can fix it... I want it to LIVE ON!

 

No one has any insight on this?

 

Suggest checking clearances on #4 valves. Excessive gap would indicate a bent/stuck valve or carbon causing incomplete closure.

A leak-down cylinder test will confirm where the compression is being lost; valves (intake or exhaust) or by cylinder rings.

A cruder test is to install oil into #4 and see if compression increases temporarily. If yes, then leak is likely past rings. If no, then valves.

Also suggest repeating cylinder #4 compression test in case you made an error in gauge hookup.

good luck