Fuel questions for 91 civic 1.5 liter?

My civic is getting worse. I know enough about engines to be dangerous. When the problem started I suspected an old ignition system so I changed everything.. cap, rotor, wires and plugs. No changes.

What it does is if you drive at a constant speed it stutters and loses power.

My next thought is it might be injectors. This car has a throttle body with two injectors. What I have to do to drive without sputtering down the road is accelerate very fast to the speed I want, then coast until I lose 5 or 10 mph, then give it the gas real hard until i get back up to speed and then coast again.

It kind of seems like one of the injectors might not be doing it's job due to the fact that when I give it a lot of gas and it needs to use both injectors its fine, but when I smooth out and try to hold a constant speed and only the primary injector is needed it sputters. (My logic of how the injectors work and when in this throttle body may be very wrong.. I said I knew enough to be dangerous)

If anyone has any (helpful) opinions on what might be wrong or what else I should check before shelling out money for new parts that may or may not fix the problem I would really appreciate it.

Oh.. almost forgot.. When the car is cold and I start it it skips and sputters very badly until it warms up. It idles very nice after its warm.. doesn't overheat..accelerates fine until you get into higher rpm's (4500 or so) then it skips and sputters unless you put your foot on the floor.

I know there are some honda ppl out there who know exactly what is wrong. Show me how much you know about Honda's and save me some time and money and possibly a long walk in the snow when it finally does take a diveFuel questions for 91 civic 1.5 liter?
I had the same problem on my civic. Although i never got it fixed i was suspicious of the (tps) throttle positioning sensor. I would have it at cruise speed maintaining it and it would sputter. then i would punch it and it would react.



I went through hell. i chipped the ecu, i changed like two sets of cables, rotor cap. i even took out the distributor and it was all good. i changed fuel pump, fuel filters.. you name it i changed. it.



The best thing you can do to pin point the problem is to take it in to a shop where they can run a diagnostic check up on it. that way you wont end up spending so much money like i did!



Good luck and if you ever find out what it was email me, im curious!Fuel questions for 91 civic 1.5 liter?
Change your fuel filter and replace the service screw with a fuel pressure gauge when you re-install it. A fuel filter is $12 and a fuel pressure gauge is around the same but will easily tell you whether you have adequate fuel pressure. You should have between 30-40 PSI of fuel pressure when you initially prime the fuel pump.



This will eliminate a clogged fuel filter and tell you whether or not your fuel pump is going bad.





As far as the idle goes, you should check/clean the idle air control valve and test the fast idle thermo valve per the service manual directions.Fuel questions for 91 civic 1.5 liter?
I would try unplugging the map sensor and see if it makes any difference at all. if that does not work try replacing the whole intake manifold you can find dpfi manifolds on ebay, junkyards, or parts cars for under 50 they dont go for much there not in demand

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