I have a 1991 Integra GS 5 speed with 200k on it.

Car ran fine, took it on a short road trip (4 hours one way), was driving the car easy, and about midway cruising at about 55 mph It developed a misfire. I've owned the car for 3 years with no issues until this. (other than a fuel relay)

*Idling* - So the symptoms are, It idles just fine (maybe around 700ish rpm), doesn't misfire when idling. You can also rev the car up with light throttle (maybe 10-25% throttle) all the way up to 4-5k with no issues (didn't rev it higher than that). But if I attempt to rev it up with heavy throttle, it feels bogged down and struggles to rev. (no misfires).

*Driving* - When you start from a stop, it falls on it face for a second then bucks you back into your seat from it picking up and going. Once moving with normal driving (maybe from 0-65 mph) keeping it under 3k rpm, it misfires about every 2-4 seconds and you can feel it really good too. If your're on the highway doing over 3k rpm 65+mph it starts to smooth out and it won't misfire.

*Driving* - Also It has a loss of power, kind of like revving it with too much throttle (like I mentioned above) It just feels extremely bogged down and sluggish and struggles to get over 5k rpm. (doesn't misfire during hard acceleration, at least it doesn't feel like).

The car doesn't have any misfire codes, the only code present is 17 (VSS) but It's been that way for a long time. (my speedo stopped working).

Things I've done so far have been Plugs/Wires/Fuel Filter/Reset the ECU. When I pulled the plugs, Cyl. 1-2-3 were all smooth burnt up, extremely white tipped, and Cyl 4 was black and wet. All 4 plugs were soaked in oil on the threads and I had slight oil seepage from all the plug holes tube gaskets. (ordered a valve cover gasket kit already). I've also tried disconnecting the Cat which ruled that out. I've also sense then put a new tank of 93 octane in it with injector cleaner. So it couldn't have been from bad gas, I don't think anyway.

The next things I planned on doing was check the timing to see if it jumped a tooth, cap & rotor, injectors, then fuel pump. Because 3 plugs were burnt out, It leads me to believe it's somehow fuel related, but why would 3 be burnt and 1 wet?

What are yals thoughts? I've done some research on this but I want to know what yal think it could be. I really appreciate you guys.

 

def check cam/crank mechanical timing.
if no valve adjust in last 2 years then check that.
throttle position sensor test is also good idea.
air in cooling system can also do this
but if no coolant loss then not likely.

https://honda-tech.com/forums/honda-...hread-2830131/

 

I appreciate the response, I'll need to pick up an ohm meter and test the TPS and see if it's getting the right voltage to it.

My buddy has a timing light i'll have to borrow from him this weekend.

I'll report back maybe later this weekend or maybe Monday.

 

Uneven injector spray pattern. I would have them ultrasonic cleaned/rebuilt/tested. Should only be $15-20/injector. This is something that should be done as basic maintenance every ten years or so.

 

Yeah one of my first thoughts and still is, is that it's the injectors.

Though I can just get a brand new set of Denso's for $50 for all 4.