I need some help I'm semi new to this. got a 98 one ton 24valve 5 speed. Here's my problem Every now and then I will lose power have maybe 1/4 throttle acts like it's going into a limp mode sometimes check engine comes on. It stays like that for a little while sometimes I can cycle my key a few times and get full power back I don't have anywehre to check codes also if I park with the nose up I lose prime takes 15 seconds to start or so. I'm thinking possible air leak hopefully not injection pump I need to know where to start I'm good at fixing gas engines but I love diesels and this is my first major problem. Oh ya and when I get off the highway it seems to run a hair rough when it idles. thanks

 

Your going to have to find a scanner and check for codes. AND you need a fuel pressure gauge to check the condition of the fuel pressure gauge.

 

I think the 98.5s had a hard line line between the fuel filter and injector pump that was known for cracking, may be where your losing prime.

 

ya it has a hard line and I'm going to autozone monday to get codes read and look for a crack tomorrow although I don't see any obvious leaks I can smell a hint of diesel would that cause it to throw a code?

 

p1693 and p0237 throwing both codes and I'm running 14psi on idle about 10 on throttle can't find any leaks runs like a champ after resetting just waiting for it to happen again any help would be appreciated.

 

iI have a 24 valve 98 three quarter ton with a rebuilt tranny , a new filter and a complete diagnostic on the lift pump which is within specs after 290,000 miles. My truck goes into limp mode after 20 miles or any large hill. It slows to a stop and I shift to low and take off with full power. I have no codes except one injection timing code. The limp mode seems to trigger and reset itself. I read the many dead peddle posts and wonder why there is no code for limp mode that limits fuel and throttle response. I suspect the brain has a communication problem. Do lift pumps go intermittent? I am confused as well.

 

Mine seems to be a 1/4 throttle situation I have normal power to about 1300rpm then it slowly climbs seems to happen after I let truck idle. lately if I fire it right up and drive it does ok Just drove to my inlaws did great then I let it idle for about 10 minutes while I was airing up a tire and had no power going to town. reset and runs great on the way home after checking and clearing my codes at auto zone.

 

P1693 - Companion Code,P0237 (M) Map Sensor Voltage Too Low MAP sensor voltage input below the minimum acceptable voltage.1693 code will always be in the system when a code is thrown.

 

do you have a fuel pressure gauge? I suggest your start your own thread

 

mine had a p0237 code and i cleaned map sensor and it worked for a while. i screwed it up when putting in smoke switch. i ended up replacing it and problem gone.