95 geo prism 1.8L LSI with hesitation problem

Posted at 08/27/2008 7:16:47 PM in 95 geo prism 1.8L having serious run problems

95 geo prism 1.8L having serious run problems

my check engine light came on and i noticed no difference in driving or idleing so paid no attention to it. About 5 months later a reacurring problem developed. the car would sputter and hesitate when u try to accelerate, the first time it happened i was almost T-boned for the malfunction. now the problem has been going on for 6 months. Dealership pulled code and sent me after a exhaust gauge regulator. $375 later and my run problem was still there. They also cleaned my fuel lines out whic did improve its performance initially, but within a month the problem was back. The car idles when it is still cold just fine, but once it reaches opperating temperature it picks up the hesitation, and if u try to accelerate it sputters and if you keep trying to accelerate it will die, sometimes giving a puff of smoke out of the air box (smells like oily exhaust). my car is not burning oil, i rarely hav to add any oil between changes, and i hav never seen the temperature gauge rise above normal opperating temp. I hav stumped many of the local mechanics, they are willing to throw parts at it, but its my money that is buying the parts… I have replaced my spark wires and plugs and cap recently, i also put a fuel filter on it. help please

I have the exact same car, year and engine and experience the exact same symptoms. At a mechanic’s advise, I replaced the fuel pump and fuel filter with no success – same problem. I’m still trying to analyze the problem.

Check the operation of the Throttle Position Sensor. If this is not operating correctly the ECM will be getting erroneous information. On engine transitions like acceleration the ECM relies on the MAP, IAT, and the TPS to calculate injector pulse width. The ‘puff of smoke’ is a back fire which is usually an indication of a lean mixture problem.

Hope this helps. Post back when you find the solution to this problem.