I've been having a problem with my 94 DI and can't seem to get it figured out.
Symptoms: after sitting for a day or so, very hard to start. Yesterday it started up almost right away and I ran it about 3-4 min, shut it off and went in for a few min, came back and same problem.
At highway speeds while in Drive, it hesitates, as if it is "missing" however this stops when I shift to 3rd.

I have replaced the fuel pump assmebly and the fuel filter. What should I check next?
Thanks
Jim

 

What grade of gas are you using and when was it last tuned up including cap and rotor?

 

Could be coolant in cylender

 

I use only premium grade gas. Don't know when it had a full tune-up. I replaced the plugs and wires last year and inspected the cap and rotor at that time. Both appeared to be in good shape.

 

As in a blown or leaking head gasket? Wouldn't there be coolant in the oil? My wife did mention that she smelled radiator fluid yesterday after coming back from a drive. How would I check that?

 

After you start the truck go to the tail pipe and smell the exhaust, does it smell sweet?

Remove the spark plugs one at a time, what color are they?

 

In my last truck the problem was a head gasket. It didn't smoke, the spark plugs looked fine, there was no water in the oil. Slight browning on the radiator cap though.

Only way I knew for sure was pullig the spark plug and either turning the engine over with a paper towel over the cylender. Or put some kind of swab down the cylender to find coolant. That was the only thing that proved it for me.

It had A bad rough idle that only did it if I let the truck sit at first. As it got worse it would happen everytime.

Found out the perviois owner used some head gasket fix. It lasted 20,000 miles. And I repeated the process and it worked.

 

What kind of fix? Is it an additive that goes in radiator?

 

It means you need a new head gasket. Which is the only correct way to fix it.

Autostores sell this stuff called head gasket repair that runs from 20$-60$ But it worked for me. I believe it has its downsides im sure. Probably coats the walls of the whole radiator system and after a while it will probably clog the radiator.

 

I know I am going to catch flak for this, but... When I flushed the coolant on the new (used) engine install 2 years ago, I added a can of BG leak stop when refilling with Dexcool (more flak I know, but everything I have read shows the Dexcool only has corrosive tenancies when exposed to air (from a leak) other than that, it is better on aluminum than green)

The BG leak stop stays in suspension indefinitely, until it comes in contact with oxygen, so it doesn't seal up everything it touches like many other products. If something does start leaking, it will begin to seal it, otherwise it's just in there being pumped around with the coolant.