This is a problem that has been plaguing my car for roughly a year now, and at this point, it is not going away.

It started last summer, and as the weather became colder, the problem went away. I drove the car from Sept-yesterday with no issues whatsoever. During that time, I did NOTHING to the car. Yesterday I went to start the car, and it started acting up all over again with no warning.

Symptoms:

- While driving, the car "stutters". You can feel it "hiccup" as it drives.
- Give it gas, the issue stays the same.
- It is now currently backfiring if it idles
- It does this regardless of engine temp and speed.
- On occasion, it smooths out perfect. Drives perfect, powerband is beautiful...then it goes back to hell.

After I pulled it back in yesterday, I got to messing around with it.

I pulled the #1 plug wire and idle did not change. I put the spark plug wire to ground and there was spark. I put the spark plug wire back in, and nothing changed. I pulled the fuel injector wire, no change.

I unplugged the #2 fuel injector and the car stumbled. I took the fuel injector wire from #1 and put it in #2 and it brought it back to life.

I "think" I narrowed it down to a bad injector.

The car currently has 290CC Prelude injectors, and I did not have a spare, so I put a GSR (I think) in it's place. It continues to do it, but not as bad.

Things I've checked:

- Mechanical timing. Spot on. This has not been tampered with at any time.
- Compression test. 260 PSI across the board.
- Spark plugs. All are gapped the same and they all look the same.
- Plug wires (swapped them out with a known good set, same result)
- Distributor (I have a spare OEM one, same result)
- Removed the valve cover and everything looks perfect. All bolts are tight and no broken bits floating about. (This car never see's anything higher than 7K RPM).
- Dropped the exhaust and it's clear as can be.
- Fuel pressure is as it should be.
- ECU has been swapped with a known working unit.

So for now the car runs, vtec engages, no CELs.

Occasionally it runs like a dream, but then whatever it is "happens" and it goes back to ****.

What I'm hoping:

1. The bad H22 injector was old and getting stuck and the GSR one is too small and still allowing it to act wonky. I have no other local H22 injectors to swap as all my neighborly car guys are V8 guys who scoff at my 4 cylinder. My local Honda friends do not have the H22 injector I need.

2. Gas station is switching over to it's summer blend and I have a tank full of ****.

Any and all input is appreciated.

 

replace TPS and see if it changes. be sure to calibrate it properly.

 

I replaced the questionable injector with a "mystery"injector. I believe it to be maybe an old GSR unit? I'm not sure. It runs a little bit better, but it's not the solution.

I bought a noid light test kit, and all the injector leads from the ecu are pulsing correctly.

I did notice that it idles much better and only REALLY stumbles on acceleration. This leads me to believe that when I "get on it", the mystery injector is not enough for the load.

On a borrowed scan tool, my TPS is reading and functioning correctly.

A local is donating a set of Bosch 330s for me to drop in on friday/Saturday.

I'll update once those are in and running.

 

a dying tps will function fine most of the time but will have "holes" where it returns a 0v value and causes the ecu to cut fuel which feels like the stutter/stumbling you describe.

anything other than stock injectors will cause an issue without a retune, and if the new injectors are significantly different the car may not even start. you cannot change injectors without recalibrating your tune.

 

I put in the 330s and everything APPEARS to be smooth. I only drove it for about 5 minutes or so, and once it came to operating temp, it behaved as normal.

I'm going to flog the **** out of it tomorrow, as the weather will be clear (currently snowing) and it'll be daylight.

 

My distributor would act up on hot days causing a miss. It usually got worst the hotter it was. I replaced and it solved my problem. Might want to borrow a dizzy if the injectors didn't solve you problem.

 

You should check the resistance of the injectors. The bad one will not have the same resistance as the rest. I have also had problems with a bad connector, where the wires did not make a reliable connection inside the plastic connector housing!