Lopes on startup

Delta161

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Whenever I start my truck it has a pretty noticeable lope and you can feel the truck shake. Once I put it in drive and accelerate it clears up after a few feet and runs fine. It has new stock injectors and idm. I tried replacing the gray cps with the black one but there was no difference. The truck is stock. Any help would be appreciated.
 

Arisley

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How long has it been since an oil change. What kind of oil are you running. What is your ICP. Could be a sticky IPR.
 

ITUKMOR

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we had several trucks that "romped" on us, not sure exactly how close that is to what you have going on but it was the tranny range selector switch. try this, start the truck and while it is acting up shift it into neutral. if it quits as soon as it hits N, the switch is bad.
 

bluedge8

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we had several trucks that "romped" on us, not sure exactly how close that is to what you have going on but it was the tranny range selector switch. try this, start the truck and while it is acting up shift it into neutral. if it quits as soon as it hits N, the switch is bad.

interesting, mine will romp too but seems more ambient temp related, colder it is the worse it does it. If I wait a while longer than wts light, like double it becomes way less or non existent. I am assuming mine is gp related and cyl's just aren't firing- also the worse it does it the more gray smoke I get at start up. and the romp is usually less than 3 seconds total.
 

ITUKMOR

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When this happens it will romp good for 30 seconds or more if you don't shift it or bring rpm's up. Your issue definitely is GP or GPR related.
 

ITUKMOR

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Tell me about it. And what is even worse, both of these trucks ended up in our shop basically within a week of each other and they came from farms almost 250 miles apart.
 

Blowby

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OP hasn't replied yet to any questions above. I'll add a few more: How many miles since injector install? Did you install these yourself? Did you change the oil after the install? Why did you swap the IDM? Did you scan for codes?
 

Arisley

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OP hasn't replied yet to any questions above. I'll add a few more: How many miles since injector install? Did you install these yourself? Did you change the oil after the install? Why did you swap the IDM? Did you scan for codes?

I was starting with basics.

Nevermind, codes is about as basic as you get.
 

Delta161

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Sorry I took so long to respond. I had the injectors installed at a local performance shop. The idm was replaced because it was shot and the truck wouldn't even start. They were both changed about 200 miles ago. I haven't changed the oil yet.It was changed about 1000 miles before the injector install. I looked at the icp sensor and it is missing the rubber piece and the inside plastic piece and it has a bit of play when plugged in. Could this be the problem.
 

Arisley

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Could be. And the oil should be changed after the first heat cycle on an injector change. Lots of other fluids go down on top of the pistons, and from there leak down past the rings. That and get pumped up on top of the head when purging the cylinders and from there leak back into the crankcase.
 

Tom S

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Alright I'll get a new icp pigtail and change the oil. We'll see if that works. Thanks for the help.

Here is the part number I have for the ICP pigtail at International.

ICP Connector with Pigtail
(International) 2501105C1


I have also found those connectors on GM vehicles?? at the junk yard before. If you just need the rubber seal that would be an idea. I have not personally purchased one off that part number above.

I also came across this information as well for being the same connector.

GM part number 10096181 3-wire coolant temp sensor for a 1993-1997 GM LT1/LT4 motor
GM part number 12102748 Connector pigtail (incl. terminals)
 
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