hard to start cold and missing

have a 1996 blazer w in the serial.

just started this. but when the truck has sit in the cold for a day or so it is a bit*h to get started after it finally starts it runs rough and misses. after it warms up to running temp everything is fine like it never happend. also had a friend check the fuel pressure with gauge it was around 62 while running and about 62 when key was just on. didnt drop any pressure after it was off either. i also replaced the ignition control mod. and that wasnt it.
any ideas with this?
tune up was about 15 to 20,000 ago new wires cap filters and rotor button and plugs.

This is exactly the problem I am having. Mine has 180K miles and had a full tune up 30K miles ago. Last night I installed a fuel filter...it did not help. This weekend I am going to install a new CPI injector/regulator unit. The only other possibility I can think of is the fuel pump.

One question I have for the experienced folks: Once I remove the plenum, if I don't see any washing from leaking gas, can I assume the CPI unit is good and not change it out? In other words, does the CPI have to be leaking to be defective/ worn out?

Have you scanned it for any codes...code 14 or 15 would be the ECT and if you get a 23 or 25 it could be your IAT sensor...both of these could be a culprit, but before jumping to a conclusion, test, test, test..

Have you scanned it for any codes...code 14 or 15 would be the ECT and if you get a 23 or 25 it could be your IAT sensor...both of these could be a culprit, but before jumping to a conclusion, test, test, test..


just got back from auto zone no codes at all!

got me baffled.

There is a way to test both of these sensors, relatively lenghty though, you will need a multimeter...let me know if you want the directions...

Have you changed the fuel filter lately?

if you are serious i will try this but if i am getting good fuel pressure... how can the filter only cause a problem when its cold?

fuel filter was replaced about 10,000 ago. at time of tune up

Have you had the truck scanned for trouble codes?

This is exactly the problem I am having. Mine has 180K miles and had a full tune up 30K miles ago. Last night I installed a fuel filter...it did not help. This weekend I am going to install a new CPI injector/regulator unit. The only other possibility I can think of is the fuel pump.

One question I have for the experienced folks: Once I remove the plenum, if I don't see any washing from leaking gas, can I assume the CPI unit is good and not change it out? In other words, does the CPI have to be leaking to be defective/ worn out?

You may be having the same symptoms as the original poster who has a '96 which is not CPI. If you are changing a CPI unit, your vehicle must be a '95 or older vehicle.

To answer your question, yes, the CPI could have issues other than washing. Remember, all six injectors are a part of it and if the nozzles are leaking, that is a problem and the unit will need to be replaced since the individual injectors cannot.

Most times, the regulator will wash before the injectors go or the nut kit will leak.

Check for washing and get back.

In the CPI system there is actually only one injector and sit poppets valves set to open at a minimum pressure of 54-56psi.

Problems that occur are usually the poppets sticking closed rather than sticking open.

In the CPI system there is actually only one injector and sit poppets valves set to open at a minimum pressure of 54-56psi.

Problems that occur are usually the poppets sticking closed rather than sticking open.

I'll remember to tell the customer when he comes back in the shop from last June who had a drooling one in a '94 Jimmy that had a piece of crap stuck in it that it wasn't really drooling and washing #6 cylinder that it was really stuck closed and that the flooding was all a figment of the CPI's imagination.

Did I say you were wrong?

I am just stating that in most cases they don't pop open at all so simmer down there.

yes had it scanned at autozone... no codes what so ever.

went out this morning to start it and go up town... hasnt been started in a few days, it was a royal pain to get started... ended up running battery down and had to jump it... finally got it started and it missed and sputter for a lot longer this time... also it is alot colder outside than it has been also...

one other thing... i noticed it i accelrate rather slowley it hits one spot in the rpm's and misses like crazy rite before it changes to second and 3rd gear... if i accelerate like half way while its doing this it stops missing and runs like a scalded dog... i just dont understand what its doing?

I would check your cap and rotor again. They could be causing this.

Also, make sure your battery is performaing properly and have it fully charged.

I would check your cap and rotor again. They could be causing this.

Also, make sure your battery is performaing properly and have it fully charged.

This is a red letter day, the second time I am agreeing with LT (just kidding). He's right, check the cap and rotor and perhaps the wire set. Your problem sounds like ignition and for the cost, it's worth it.

This is a red letter day, the second time I am agreeing with LT (just kidding). He's right, check the cap and rotor and perhaps the wire set. Your problem sounds like ignition and for the cost, it's worth it.

This is gettin creepy......

Hey guys, just an question here...but he said when he tested the fuel pressure he was getting 62 psi both before starting and while running .It is my understanding that once the engine starts and vacuum is applied the pressure is to drop by 3 to 10 psi...could this be relating to any of these problems..

Might be.

If so, swaping in a new pressure regulator should fix it if that is the case.