Honda 91 Accord, Misfires when in gear.
On start 1500 to 1350 RPM in Park and Neutral. Cycling through D4 or R ends up with some misfire and about 1000 RPM in Park or Neutral.
In any Drive or Reverse with brake RPM drops to 750 and misfires with vibration.
Check Engine light off, and stays off when trying to read OBD1 codes with blue connector
by glove compartment
Shop replaced alternator 9 months ago. Used transmission and TCU about 15 years ago.
Recent Moonroof and driver’s side windshield water leak problems coinciding with
intermittent electrical issues, (driver’s passive restraint, passenger window) not working then working.
Passenger carpet (on top of the TCU ) is dry.

When engaging the gear, do you have a misfire when idling, or also when driving?
Both. Low power when driving not safe in traffic.
When driving the car, does your engine perform better at higher rpms, or does it run poorly at all rpms?
Yes all rpms poorly, low power especially uphill. I tried D3 and smooth but low power at 3k RPM.

 

There isn't an obvious starting point for troubleshooting. Being a 91, you can't plug in a scanner to get direction either. Any chance you filled the gas tank not long before the current problem started?

Are you doing your own work or taking it to a shop?

For simple stuff, test the battery voltage when the car isn't running and also when it is running. Remove the distrubutor cap and rotor and look for signs of wear or corrosion. Check for a clogged air filter. You could pull the ECU and TCU and open them up to see if any obvious corrosion/damage is on the circuit boards. Fuel pressure is easy to test, but you need a not common adapter on the fuel rail. Put a link to a thread below where someone had an adapter made and used a loaner tool. You could do a compression test while also looking at the spark pluge.

There are other things I can suggest, but this could become a long list of posibilites.

https://www.hondaaccordforum.com/for...st-port-63807/

 

Thanks. Seemed to be getting worse over a few hundred miles, under power and slow shifting from 3rd to 4th etc.
Taking to shop.
New information. When warm have the same missfire in Park and Neutral, RPMs cycle up and down 600 to 1000.
There is an oil leak around the distributor area? and sludge from it is on parts below and to the rear.
Had a different problem on a 1990 subaru. A shop changed the timing belt and a while later the idler/tensioner slipped.
The ECU would make up the difference when cold, but once it warmed up the car would stall at a stop. Took a second shop
awhile to figure that out.

 

Keep us in the loop for what the shop figures out.

 

An old school answer is pull spark plug wire from plug with engine running under load with someone holding the brake pedal down at the RPM of the miss. You need a insulated spark plug pliers and the cylinder with a miss will show little to no change when wire is pulled. Be careful not to get shocked.

 

Thanks for your help.
Shop reports, Found cyl 2 plug hole full of oil. Plug wire is swollen.
Replaced plug wires, did valve cover gasket kit including
spark plug tube seal.
Recheck and cyl 3 had hard misfire. Distributor cap contact cracked.
replaced distributor cap and rotor.