I have a 1995 Camry with the 4cyl 5sfe engine and a manual transmission with about 120K miles. It’s been very reliable overall, but lately it’s been exhibiting some strange intermittent behavior. When driving at a steady speed between 2-3K rpms, it’ll sometimes experience a momentary power loss. There’s no stalling, but it’s as if I’ve hit a stiff headwind or the brakes have been applied and then release. It doesn’t seem to happen when accelerating, but as mentioned above, it’s most noticeable when maintaining a steady speed. Sometimes it’ll be very quick like it’s bucking and other times it’ll last a full second or two. It’ll do it in all gears at both relatively low speeds and highway speeds, so there’s no pattern there. There is no check engine light when this happens, but I have not yet attempted to check codes just in case it might be storing any. It’ll happen when the engine is both cold and at normal operating temperature. I’ve also tried to observe whether or not the tachometer drops when it bumps, but haven’t really been able to discern that due to the usual momentary nature of the power loss.
The coil on this car is integrated into the distributor and I read somewhere that it’s common for these to start to go as these Camrys age and accumulate a lot of miles. I also read that it’s common for these cars to hesitate due to internally leaking fuel pulsation dampeners. The AC compressor makes a little noise, and sometimes it almost feels like what you would expect it to feel when the compressor kicks on, although the jolt or 1-2 second sustained power loss, depending on what occurs, feels stronger than that. Plus it’ll do it with the AC off, so that doesn’t seem to be a possibility. Other than this problem, the car has no issues whatsoever. It’s quiet, uses very little oil, idles perfectly and maintains optimal operating temperature. The miles are about 75% highway since I’ve been using it mostly as an airport commuter car. Most essential maintenance items, such as the clutch, timing belt, water pump, oil seals, PCV valve, thermostat, radiator, motor mounts, etc. have been replaced within the last 15K miles, and most are Toyota OEM parts. Plugs, wires, cap and rotor have all been replaced within the last 10K miles, again with Denso plugs and wires, but aftermarket cap and rotor. I did feel up under the distributor and got some fresh oil on my fingers, so the o-ring might be leaking a bit. However, I don’t know yet if there is any internal leakage inside the distributor itself.
I’m going to tear into it a bit, but I wanted to see if anyone might have a hunch as to which direction to look first. Would you suspect a spark issue (again, no CEL illuminates), or something more like a fuel delivery issue? I also wondered if it might be something like the TPS or perhaps a cam or crank position sensor on the way out. Thank you in advance for your ideas.