Ok, i'll try to keep it short and simply. I purchased this car from inline-pro. It used to be one of their race cars. I was going to buy it as is, boosted and built motor, but sold my car to late, so I got it with a jdm auto b20 engine (on the right 98 manual usdm ecu and manual tranny).

-The crank sensor bypass is done and rechecked.
-The iac meters ground on black and 12volts when the key is on on the other wire, so I assume it's ok...)
-replaced the plugs, wires, cap/rotor, coil.
-did the valve adjustment...twice
-even swapped ecu's!

The car gets a misfire and randomn misfire on the highway only! I can go to and from work for weeks with no code, but once I cruise on the highway at 80mph, it intermitently goes off. Whenever I get on the highway I have to have a scan tool.

Also the iac has been swapped out 3 times, and it still doesnt work. That code doesnt come on as often anymore, but still comes on, and when it does it drives like crap.

So I have been getting codes, iac 505, random misfire 1399, #1 misfire, and evap now, but thats because I changed to a larger throttle body and it doesnt have the nipple to connect the hose from the TB to the evap canister.

So any ideas?

 

ttt

 

no guess?

 

ideas?

 

up.

 

well I didnt exspect anyone on here would have any idea. Worth a shot I suppose.

 

Pull the plugs and see if cyl#1 looks different than the rest.

Also, if you have a scan tool pull the freeze frame data for P0301 and P1399 and look at the fuel trim. If the number is positive, the ecu is adding more fuel than normal, so it should be a lean misfire (air leak, fuel delivery problem). If the number is negative, I'd be looking for ignition problems.

I just had a 2000 odyssey at work that was missing bad and idled like ****. The main code was P1399. I did a quick power balance test by unplugging 1 coil at a time(coil on plug). Pulling coil #2 didnt make it run worse, so I knew that was the bad cylinder. Also that plug looked like crap. I swapped coils around and confirmed it was just a bad coil. It turns out just 1 cylinder going down usually sets the specific code, but can also set 1399 for random multiple misfire.