I have a 1999 Honda Accord. WHen real hot outside generally over 85 degrees hard to start-at times having to press on gas pedal to start. I have been keeping gas cap slightly loose as friend thought it could be vapor lock related. When it is cool not hard to start. I spoke to a mechanic who wondered if it was ignition switch related. No codes were showing up when checked a few weeks ago. Twice in the past week the car died while I was driving-once at a light which was difficult to start again but did with success after releasing pressure out of gas tank. Today while driving it died briefly with indicator lights aglow but I pressed on the gas it kept going without stalling but it was close. No indicator lights are on the vehicle except for the maintenace light. The weather today is around 78 degrees-I am afraid to drive this thing far these days now that the weather is getting warmer here in Michigan. WIll keeping the gas cap slightly ajar without screwing the cap on tightly hurt anything as per the manual it says to keep it on tight. Any suggestions would be greatly appeciated. Thanks!! :)

SOURCE: 2000 accord check engine light

i would look into haveing the egr valve, injectors or fuel filter looked at 

SOURCE: Fuel pump not coming on

fuel pump operation on your impala is controlled by the computer. It activates the fuel pump relay when ignition is turned on, but only for a few seconds. This is called the fuel pump prime. When the computer senses a crank signal (upon start up) it will activate the fuel pump relay constant. I have found more problems with the fuel pump relay than anything. Vapor lock will not cause a no start unless it is in the fuel lines. GM systems use the manifold air temp sensor to allow for quick starts when hot......increases fuel injector on time. An intermittant fuel pump relay or bad pump will cause a no start any weather.

SOURCE: 1999 Honda CR-V rattles during acceleration

Hey. Same thing happened to me. There are rocks or debri stuck in your catylitic converter. Go under your crv and knock on it. You wil hear the rattle. Usually you can just pry it out from the openings.

SOURCE: 83 Rx7 stalls when cold unless I keep applying pedal pressure

these cars are carburated motors and need around 10 minutes to warm up because they operate at higher temperatures.

SOURCE: We have a 2005 Honda crv. Malfunction indicator

Hello Michael.
While your fuel cap may still be an issue there are many other items that may be at fault. It's possible the fuel cap tightening is a coincidence and something else is causing the problem.
There are a few hundred possibilities that could turn on your MIL.
First thing that needs to be done is verify what the code is that turns on the light. If you are in the USA Autozone will give you a free scan to start you off. Then you can begin to home in on the problem.
Best of the festive season to you.

KL