Engine Performance problem
1986 Honda Accord 4 cyl Two Wheel Drive Automatic 131000 miles
Too much engine vibration when idling; the car rattles as it was going to fall apart. Engaging transmission amplifies the rattling. But once the engine is above 1,000 rpm the vibration subsides and car runs fine, gears shift smoothly.
No misfire felt; checked unplugging each wire to see difference and you can note the difference when a spark wire is unplugged. Same for fuel injectors; when unplugging one of them idle becomes irregular.
The other driving symptom is that when cruising at about 2,000 rpm (about 45-50 mph) I can feel like a slight hesitation; engine does not seem to have too much power at that speed range. Engine has power at highway speeds up to 80mph (I did not press further)
Car passed emissions without problems
Things I checked/replaced
Distributor cap/rotor/wires/spark plugs: new; wires resistance about 1k ohms.
Ignition timing adjusted. Mechanical and vacuum advance work including the cold advance.
Oxygen sensor replaced. Temperature sensor seems to work as engine changes behavior (idles slightly aster) when unplugging it with engine hot
Timing belt replaced and set at right timing @ TDC " white mark" (someone had confused the TDC mark with the ignition timing mark and car died when idling. I did this when replacing all the seals (car was leaking oil badly). Now it does not leak any oil; also repaired oil leak inside distributor (new shaft seal)
New PCV valve works OK. EGR valve works OK (no leaks)
No vacuum leaks, steady vacuum at about 20 mmHg at idle.
All engine mounts replaced.
Fuel pressure ckecked about 39 psi at idle with pressure regulator vacuum hose disconnected; pinching return fuel hose sent pressure up at about 70 psi (so fuel pump is OK?)
New fuel and air filters
I thought about sending fuel injectors to cleaning and removing intake manifold to check for carbon deposits at the intake valves. What else may be wrong?
Friday, December 26th, 2008 AT 9:54 AM