Hello my 88 300 i6 is a stick shift it has new intake gaskets new fuel pump great fuel pressure fire right up cold like a brand new vehicle but after you drive it and the engine's hot you have to press the pedal to the floorboard crank on it struggles to start but you have to keep your foot floorboarded for at least 10-15 seconds after it fires up it'll sit there and sputter and miss and struggle to pick itself up but when it does it runs like a new vehicle hauls *** and everything doesn't skip a beat seems kind of like vapor lock but it's an EFI so it can't vapor lock right if so what do I do thanks and yes I have checked the spark plugs they're all burning as they should no head gasket no oil burning compression is even decent not great but decent

 

I forgot to mention it turns over really slow also when it's hot but it's a brand new battery good terminals Good grounds act like it has way too much compression sort of thing

 

How long has this been happening and did anybody do anything with the timing ?

Was it checked and if so, how? Please explain, thanks.

What I would suggest is when you checked the plugs, did you check them before starting COLD ? Might be a badly leaking injector and it might show up as a wet plug on one or more cyls..
There is a possibility extra fuel is getting in there and when cold a rich mixture is not as bad as when hot. We need to take these things one at a time to eliminate them separately..

 

Timing is set to factory specs and when you said about checking the plugs I've checked them both hot and cold all are dry and that good light brown color the injectors on these engine are real easy anyways Ill probably just replace them maybe there sticking closed or something.

 

When checking the timing, did you separate the spout connector? If not, would explain why timing could be over advanced..
That is why I asked to explain how you checked the timing..

 

Yeah I removed the spout connector I've been working on vehicles a long long time I just haven't ran into a situation like this before where nothing I'm doing is changing the problem that's why I've created account here I just don't know what else it could be besides changing the injectors at this point because as I've mentioned it's got new fuel pump in the tank although it still got the original inline high pressure pump but it works fine good feel pressure spark is great it ain't got no vacuum leaks this might just be something that I have to live with