My mothers 1994 volvo 940 is having a problem's 1st is: when it is started in the morning. Sometimes it starts up and misses slightly until it is reved about 3000rpm. Then about once a week it tries to start but won't for about 5 minutes of cranking and holding the gas to the floor then it finnaly starts and misses very bad. After it gets started in the morning it starts and runs fine all day. the next question is concerning the timing cover. It has been falling apart for a while and I ended up pulling the top half off. Is it ok to leave it like this temperarily or not? And how hard is it to replace the timing cover, timing belt,and front cam seal all need replacing. A mechanic diagnosed the car and said the missing in the morning was from a bad temp. sensor. I replaced the sensor and it didnt fix the problem. The car is a 94' 940 with a N/A 4 cylinder. And help would be appreciated. Thanks. Forgot to add that the acceleration is a little boggy like it's starving for fuel of fire