91 olds cutlas supreme 3.1 set for 6 months now has a miss and to slow of idle at a stop light. has about 65,000 miles. feel surging at about 40mph doesnot burn extra gas as great millage 1600 mile trip last week. Injector dirty? put in seafoam but still the same after burning out that tank of gas…
The 3.1 is notorious for clogging fuel injectors. They are also notorious for coil packs going bad, which will also cause a miss. I’m betting on it being a fuel injector, though. Try to find a shop that has BG flush equipment and have them do the three part intake/fuel system treatment. This will include a can of 44K for your gas tank, a can of cleaner for your intake, and the most important one, a can of injector rail cleaner. That stuff will clear up a dead 3.1 injector every time. I have used it on my own vehicles, as well as customers’ vehicles, with these results. It will probably run you around $100, which is much cheaper than replacing an injector. I recommend BG only because it works from my personal experience.
How old are the plugs, plug wires, gas and air filters?
Thnks will consider after checking out the plugs.
wires about 5,000 miles ago plugs looked perfect then filtersare new. will check out the plugs
a long road trip is the just the thing to clean you plugs, so I doubt it is the plugs. But it could be, if you oil consuption is high, or the mixture is rich. How hard is it to get to the plugs on this one? If not too hard, checking the condition of the plugs will tell you a lot about your engine.
Hi pulled the plugs they all looked fine but installed new ones and new spark wires. Air filter is new. Still runs too low at warm idle but fine when engine cold. My gas mileage on trip was great. Wish the idle screw was adjustable would just speed up the idle a little any other ideas?
Man pulling the coil pack is sure a pain once i have it checked out how c n one tell if the ERG valve is bad if its not the coils?