Hey guys I hope one of you can spot the problem with my car.

'93 civic LX
1.5L SOHC (non-vtec)
187Km
5spd manual

When the car is just cruising along but not at high RPM (say 4th gear doing 70km/hr), cold or warm it seems to almost miss a beat. Almost like it has just missed a spark and the result was a powerless compression stroke! But it only happens for a split second and is hard to notice unless you are driving the car. And it's appears to be occuring more frequently at other RPM ranges. Currently the car has a new distributor(is there a way to test the coil?), rotor/cap, wires, plugs, main relay, new oxygen sensor and new timing belt. It never stalls or dies, I've noticed that when stopped, the idle is now getting a bit rougher as well. The fuel pump appears to work just fine, and I think if it was a pump issue the symptoms would be much worse. The fuel filter has about 10 000km on it now, and I have not checked any vacume lines or other sensors.

Any information or insight to this "missed beat" issue would be very much appreciated.


Thanks.

 

Regarding the issue above. Would anyone know the symptoms of a faulty MAP sensor? I spoke with a friend who used to be an automechanic and he mentioned that may be the problem. He said the car is reading different air pressures while it's running and that could be causing the sudden short "missed beats" while it's cruising along.

 

I'd really like to hear the outcome of this, because I have the same issue with my '92 Civic LX 1.5
I have replaced the plugs, wires, cap, and rotor. So I doubt it's in the ignition system.

 

Does it feel like it's "stumbling"? Like for that split second the car had no power? My car was doing this last year when the injectors were dirty. A bottle of injector cleaner and a couple changes of midrange gas and the problem was solved.

Just thought I'd throw that out.

 

Okay thanks for the idea. Next weekend(May 6th) I'm going to take a drive up to my dads place and I'll toss some injector cleaner in the system. I'm also going to pull the Idle Air Control Valve and give it a good cleaning with carb cleaner and then give it a shot of WD-40. I heard that this can also be part of the problem. It gets dirty and a simple cleaning can fix that and idle issues as well. I'm also going to replace the fuel filter, it's due and it also makes a big difference in gas mileage. Love how honda mounted it in such a easy to access place!

I'll post my results after I get all that done.

Oh and Yeah it does feel like it "stumbles" (missing a beat!) when it's driving normally.

 

Okay, well here's what I did this weekend. I changed the fuel filter and cleaned out the IAC (Idle air control valve). The valves dirt screen was clogged up pretty bad but the carburator cleaner removed all the crud inside it instantly. I did not spray any WD-40 into i though, it will only leave a film of oil that will attract dirt 100 times faster than before. So I don't know why anyone would do that. I have to say the idle is quite nice now. Currently I have a tank of gas with injector cleaner in it that has to be run through. I only managed to drive it for 1/3 of a tank so far. The Engine "stumble" seems to be still present unfourtunately. I'll give the cleaner a bit more time in the fuel system before I move onto other ideas of how to solve the problem.


shellebelle, what injector cleaner did you use? I'm assuming that just about any brand is going to work pretty much the same, so I tossed a bottle of the penzoil stuff in.