fuel delivery problem?

[snow drifter]

99' with 135 K. Mobile 1 synthetic oil, Chevron Techron every 5K. Ran perfect until last monday. Plugs cap rotor wires all good. No codes, or check engine light. Started running crapy with the weather change. We got some rain, and dipped down into the 50's. It idles fine, and hasn't died on me yet, but was sputtering and caughing like it wasn't getting any fuel? Now today, the weather has warmed up a little, and this morning ran not as bad.Warmer now, I just took it out and it runs much better, with a slight rough idle? I've searched for miles and came up with a ton of different things it could be. Map sensor, TPS, CPS, clogged injectors, fuel pump, cat, 02 sensors, throttle body. If someone could give me a starting point I would appreciate it very much! Thanks:repair:

[90xj06]

well seeing that it happened with weather change. try the air temp sensor. but this is just a guess. you can check the tps and map. with a multi meter. cps would make it hard to start or not start. and just die. i cant see a clogged injector changing its clogginess at different temps. it may be the o2's are not worming up. does this stop at some point or just warm up?

[anony91xj]

If the problem happened in the rain, it's possible that water got somewhere it shouldn't be. Let the car idle and take a spray bottle, just spray mist around the distributor, coil, wires, and plugs. Look for arching and see if it affects the way the engine runs.

If that's OK, check the IAT sensor with a multimeter.

If you think it's a fuel problem, start by putting a mechanical guage on the rail's test port and watch the pressure.