My truck (signature below) is beginning to act up...these are the symptoms: Up hill WOT doesn't accelerate as quickly even runs out of power at about 60-65 mph...begins shuddering a little...climbs a little short of normal boost; 28-29#, used to hit 31#...EGT's are about 900-950 (normal to a little low) and fuel pressure doesn't seem affected at all...

It shudders at WOT on the flat too but seems to accelerate with no other issues...just changed both the fuel filters about a week ago, no shudder then...fuel consumption seems the same. Cruises with no issues at all...

I'm also getting a lopey/uneven idle...

Nobody has an idea?

 

Could be a MAP sensor going bad.

 

I've been having something simular happening since last week. I'm gonna also pull and clean the IAT. I just replaced my fuel filter two weeks ago, but I think I'm gonna change it agian. I would have thought a MAP sensor going out would cause a code......maybe not. I think I'll pull it and cean it just for the heck of it.

 

does anyone remember what size it is for the map sensor?

 

I think it's a 1 1/4" socket.

 

Seems as though there's little surging going on through the whole RPM range but it's only really noticable at idle ('cause you can see it on the tach) and at RPM above 2000 WOT or hard acceleration...I'll have the codes scanned tonight...


anymore ideas???

 

Something is telling me you aren't pushing as much fuel as you used to. The lower boost and EGT #'s appear to show that. That plus the shuddering/surging and idle issues seem to suggest impending VP44 troubles.

 

I was beginning to worry about that as well but the new VP44 I put on I'd expect to last a little longer, I more than a little happy to find out it wasn't the VP44!!! I couldn't get any codes 'til I disconnected the "VA" box...but then they weren't indicative of the issue so I got Merv from Merv's Auto Repair to take a ride with his scanner, (he has a 24V near 600 HP) it scanned 0 boost while my gauge showed 18 lbs...it was indeed the "Map Sensor" AKA the "Turbo Boost Sensor"... you guys called it, thanks everyone for all your help!!!

 

Cool, glad to hear is was something easier than the VP44 (and a lot cheaper too !)

 

*takes a bow* j/k

Glad you got it figured out.

 

Darn to late. I would have guessed MAP also...I had the same thing. I replaced the VP, injectors, and sent both boxes out to get reflashed before i decided to try the MAP. Glad to hear you were a little smarter than me.

 

Whew...that had to be pricey...but hey on the bright side ya got a buch of new parts ya ain't gotta worry about for awhile!

 

I used the suggestions here for directions to look in...

 

my 02model,,,,,the map is 1 1/16 socket,,,,,,,,the iat is 13/16.....deep well............bama