Hard to start at times

My 2000 grand am 3.4L (128xxxkm) has been very hard to start at times:disappoin. It is almost as if it doesn't want to catch. The gas pedal must be pushed down in order for it to start. But this doesn't happen all of the time, only once and awhile. I have replaced the plugs and wires recently and made no difference. Any suggestions what it might be?

Check the fuel pressure.

If it is related to your gas pedal I'm not sure; however, it could be your ignition switch or master lock cylinder. I have an 01 GA and had to replace my ignition switch at 98k. Apparently the ignition switches are not very good quality.

Is there anyway I could check to see if it is the ignition switch? I am wondering if this could be related to; I seem to use massive amounts of gas lately.

My 01 grand am 3.4 is hard to start as well it was idling sporradic when the engine was on idle. I changed out my MAF sensor and the Idle is back to normal. I also changed out my pcv valve cause the exaust smelled like wrotten egg and it was consuming allot of fuel. after i fixed that problem i got a p0305 code which is misfire on piston 5 So i checked my plugs and coil and changed out my wires and the code went away. but now im still left with the car hard to start and stumbles. I have been checking every where and it leads me to to believe that it might be my o2 censor or a fuel injector but first im going to change the fuel filter wich is the cheapest. I have been all week researching this problem. yours might be a combination of things like mine i hope this helps somewhat. If i find the problem ill post it.

I changed out my fuel filter today checked my fuel pressure regulator for leaks and disconnected my o2 sensor and started the car hot and cold a couple of times and still no change im going to have to check my injectors and i might have a leak in my intake gasket cause i do have a lifter noise.

Several things could cause this issue.

But Id replace the fuel filter if its not been in the last 20-30k miles, these are highly neglected areas. And check for vacum leaks in the sir intake and around the LI manifold.

Quiet possible an injector is acting up on both these GAs. If you dont run injector cleaner or have the system cleaned profesionaly every so often you can experiance these same problems.

Here is a link with several test procedures, including the ignition switch, O2 sensors etc etc.
Tips & Maintenance (http://www.automotiveforums.com/vbulletin/forumdisplay.php?f=2148)

I added a fuel Injector cleaner over the weekend and my wife reports that the car has been turning on fine when cold I will have to check tmrw to see if it does the same thing when engine is hot.

remember ECT sensor is very important when starting. O2 sensor has nothing to do with starting since when ever you start system will always start in open loop and after several seconds depending on how hot the coolant is will go into closed loop. However if your ECT sensor is telling your pcm that engine is so and so degrees hot or cold pcm will lookup its tables and based on the temperature find the corresponding value for injector pulse width time on. So if your ect is a bit off your engine may not get enough gas pumped in for the start (remember cold engine needs more gas for start, hot engine less). Replace your ect it is only $14 and make sure all the wires and connectors are ok.. good luck.

This ECT realy has nothing to do with this issue. If it was failing the temp guage wouldnt read correctly.
Here is a link with those test procedures (http://www.automotiveforums.com/vbulletin/showthread.php?t=660655)with the temp/resistance chart for this model GA.

IMO This is more likly a fuel (delivery) issue. Either the injectors are clogged/dirty or the fuel pumps weak, could also be the fuel filter clogged.
Even a dirty air filter can cause simular issues with start ups cold or hot.

test resistances of your coils, if they get to hot resistance increases and will not send enough voltage to your plugs. someone must know resistance values for primary and secondary circuit I just remember that when you measure the resistance from the ICM side it should not be more than 1 ohm, but for the towers I am not sure.

Yeah you can check for good spark with a old plug, placed in the wires and cranking it over with the plug grounded, but dont touch it while cranking ! Spark should be bright blue.

If not disconnect the plug wire and test it. The resistance of a good plug wire should be around 600 ohms per foot, ie. 2ft=1200ohms.

If that checks out check the coil(s).
The secondary resistance, acrossed the towers, should be between 5000-7000 Ohms, if it's not replace the coil(s).

Also if no spark could test your crank sensors. Procedures for that are here... Tips & Maintenance (http://www.automotiveforums.com/vbulletin/forumdisplay.php?f=2148)

Took it to GM and got them to clean the injectors, very dirty. It starts well now and my mileage is back to normal, thanks.

I finally took the car to the shop, they put it on the machine and found nothing wrong. I asked if the Inectors were working and they said yes. so i took the car home and serviced my TB and IAC valve which was really dirty. the car starts good when cold now but it still doesnt start up good after its been running and i let it sit for a few. I noticed that the car starts acting up when the temp is 2 lines after half way point and i dont hear my fan cutting on so im going have to check on that. Does any one know at ehat temp is the fan supposed to cut on?

I finally took the car to the shop, they put it on the machine and found nothing wrong. I asked if the Inectors were working and they said yes. so i took the car home and serviced my TB and IAC valve which was really dirty. the car starts good when cold now but it still doesnt start up good after its been running and i let it sit for a few. I noticed that the car starts acting up when the temp is 2 lines after half way point and i dont hear my fan cutting on so im going have to check on that. Does any one know at ehat temp is the fan supposed to cut on?

Here are how the fans work;
The PCM commands Low Speed Fans ON under the following conditions:

The engine coolant temperature exceeds approximately 106°C (223°F).
The A/C refrigerant pressure exceeds 1310 kPa (190 psi).
The vehicle is shut off when the engine coolant temperature is greater than 140°C (284°F) and system voltage is more than 12 volts. The fans will stay ON for approximately 3 minutes.

The PCM commands High Speed Fans on under the following conditions:

The engine coolant temperature reaches 110°C (230°F).
The A/C refrigerant pressure exceeds 1655 kPa (240 psi).
And when certain DTCs set.

Thanks for the quick reply xero. Today I checked my fan relays and fuses and all is good and i heard my low speed fan cut on @ 3 lines past 200 is that 230? so maybe my low speed fan is cutting on too late. can the dealer program the pcm to turn on the fans sooner. I noticed the car is starting better now cold and warm but i do get a strong smell of fuel when i turn the car off wait a couple of minutes and start again and also the idling was good it didnt fluctuate even at 230 temp so I thought maybe that was it! Till an hour after I went to turn the car on and it started good but the idle started fluctuating again and the temp was below the 200s the only difference was that my lights were on since it was dark. Tmrw im going to test the car with the light off and on too see if it has any change. do you think it might be my FPregular thats causing that strong fuel smell

Ok I today i drove the car around again and its doing the same thing again. It starts good when cold but after its been running I park and let it sit then when i come back it will have a hard start. with the car in park the rpms are about at 650 to 700 but then they will start drop lower and lower till the car stalls or they level out and it does this every couple of minutes. When the car is on drive it wont do this and runs good. I am running out of options What could this be?

so far I have changed out my coils and my o2 sensor and my egr valve and nothing has changed I dont htink its a vacum leak cause it only does it when my engine has already been warm and i let the car sit for about 20 min. if it was a vacum leak it would do it all the time

try new ECT it was the cheapest option.

I am going to change out the ect tmrw ill post the results, thanks for the reply I was running out of options

I changed out my ect and the car is still doing the same thing im thinking now that its my my lower intake gasket has a leak

check your coolant level.

The coolant resevoir has the correct ammount, could it have an air pocket? and How can i get it out

There is a bleeder screw on the t-stat housing. I never knew that. So how I did my GP after replacing the water pump. I filled the radiator back up and would start the car and let it run for about a minute and stop the car. Then refill the radiator and continued the process until I did not have to fill the radiator any more.

yeah this model doesnt have a radiator cap, I dont think anyways.
Also the bleeder might be over top of the water pump.....

Purple arrow..
http://i28.photobucket.com/albums/c242/xeroinfinity/auto%20odds-ends/99gtundr2.jpg

http://www.automotiveforums.com/vbulletin/showthread.php?t=718130

I bled my line and nothing the car is still has a hard start when warm

Could it be the air inlet temp sensor? somebody from another site recommended I change it. What symptoms would it have.

I just ran into this problem today replace your Fuel Pump Relay, its only like $20, my 2.4L started doing that, and last time it happened i put in a used one and it worked fine until this past week, so im getting a new one tomorrow.

Best of luck.

I tested the fuel pump relay today and its working fine. Thanks for the tip anyway.

My car was acting up really bad today so I took it to the shop after five minutes of checking it turned out to be my fuel pressure regulator is bad the diaphram inside is ripped. is $260 a good price to replace it.

Not really, considering it cost about $50.00 and you can install the fuel regulator yourself. It is not very hard to install.

Well I got the car back today and its running smooth now. all that trouble for such a simple thing. Thanks to every one that replied to my posts.