1992 Honda Accord Misfire (From Hell)

For the past several months, I have had a misfire in my 1992 Accord which is about to put me into a mental hospital! It showed up one evening out of nowhere after exiting a highway and accelerating away from the exit ramp. I have worked on this problem myself, and have resorted to hiring an increasingly large number of professional mechanics (at least six as of today) to fix this problem, spending a small fortune in the replacement of a myriad of engine parts–all to no avail. Several of the mechanics have given up completely, and one of them told me to put a stick of dynamite in it.

Here’s the scoop of the car and what I have done so far: This car was purchased new by my uncle and I have driven it since its early days–so I can attest that It has been very well maintained in general and never abused (I have all service records). I bought it directly from my uncle three years ago (with about 128,000 miles). It now has a hair over 180,000 miles. The essence of the problem, in a nutshell, is this: It runs like a TOP when it’s cold, and CRAP when it’s FULLY WARM. I say “fully warm” because the misfire comes on like clockwork–approximately 10 minutes after a cold startup or 5 minutes after first reaching the normal operating temperature (where the temperature gauge’s needle rests around 40% up on the temperature gauge’s scale). It’s most noticeable when accelerating from a standstill up to 40 mph. It feels like it’s running on three cylinders (as if one or more of the spark plugs is contaminated with oil). And get this: disconnect the throttle position sensor (TPS) and it will not misfire at all, ever–but of course you’re left with other unsavory problems like the car shifting erratically, shifting around 4,000 rpm versus 2,500 rpm, over-revving in general, et cetera. So, it’s take your pick of which set of problems you want. I have decided that no misfire is healthier on the engine than the occasional high revs and the annoyance of a glowing engine light (due to the throttle position sensor being disconnected).

What have I replaced? The spark plugs, the wire set, the ignition coil, the distributor cap and rotor button, the throttle position sensor (three times–twice with new parts from Autozone and once with a used part), the coolant temperature sensor, the oxygen sensor, the entire (damn) distributor because I wanted to replace the ignition control module (and it came built-in), the PCV valve, the PCV hose (because part of it was collapsed), the entire EGR valve assembly, and the throttle body. The throttle body was the only part that wasn’t brand new because–even if you’re a billionaire and want a new OEM part–forget it. It’s not available through Honda, Autozone, Advance Auto, NAPA, or O’Reilly Auto Parts. Oh, and the head gasket was replaced when I had the timing belt and water pump replaced six months ago (so that pretty much rules out that possibility). The only things that I haven’t replaced, which I heard may have an impact (I hear conflicting stories) is the thermostat and the idle air control valve (which acted up last year but then magically cleared itself up). Being pre-1996 makes it hard enough to analyze using an OBD1 diagnostic tool, and even if you have one, there is no “check engine” light that even comes on until you disconnect the TPS. I did a compression test on all cylinders–right around 165 psi on three of them and 145 on a third. The one weak cylinder jumps to 175 on a “wet test” with a tablespoon of fresh oil deposited into the cylinder before the test. This is just the tip of the iceberg of all the nonsense I’ve gone through so far, but I don’t want to bore you to tears—or possible cause you to fall on the floor with laughter–with all the details. PLEASE HELP!