Hello, new guy here. Really need an assist!

My 1998 Accord 178,000 miles is missing on all 4 cylinders. This started under heavy acceleration a few months ago. Changed timing belt, water pump, cap, rotor, wires, plugs and coil. All that, because it was just time. But, then the problem has not gone away.

Revs fine. I can take it to the red line. Really noticable from 2500 RPM and under. HYW speeds and acceleration for passing seems fine. But, it is throwing missfire codes on all 4.

Any thoughts or suggestions are appreciated.

 

Clean EGR valve and passages. Check O2 sensor. Do a compression test. Test fuel pressure. Check for air leaks. Check ignition timing with a timing light. Pull the vacuum line off the FPR and see if fuel is leaking or you smell fuel. Clean fuel injectors. Check if cat isn't clogged. Test CYP/CKP/TDC sensors. Many things can cause that..

 

Over 100K miles, have you ever cleaned the EGR ports?

If not, go get an upper plenum gasket ~$5.
Remove upper intake plenum and clean the EGR port. Reinstall and test.

Payment can be sent to me in beer.