krawler-N-tow

2002 5spd, when I set my cruise the throttle starts dropping off and surging. I replaced my apps less than a yr ago in an attempt to fix this issue and it did, until 3 days ago. So last night I reset the apps. Drove for 1.5hrs this morning and it missed maybe 2 or 3 times. Cut the truck off for 30min then on the return drive as soon as I set the cruise it was completely all over the place. I Haven't had a chance to check for codes, I'll be with the truck tomorrow and get to that asap. I'm desperate to get this fixed. I have a roughly 5000 mile trip coming up next wk. Thanks for any help!

KATOOM

Fill out your signature so we know what you've done to the truck and then we can better assess the questions.

Some of the 2nd gen trucks are vacuum controlled cruise and some are electronic. No one seems to know why or what years have which one either so if you know which one you have may help understand whats being affected.

That said, ANY electronic devices you have on the engine can potentially affect the cruise. Especially any performance boxes. The more aggressive the hp box the more aggressive the cruise control surge.

If you do need a new APPS then I'd suggest TIMBO APPS as they're better and cheaper than anything else.

krawler-N-tow

I've always had my signature filled out, not sure the why it isn't showing up? I do have a comp box on the truck but it has not been powered on in wks.

KATOOM

Remove it and see if that helps.

krawler-N-tow

I completely removed the comp box. Drove on cruise for about 10 minutes with no issue, made some stops in town then got back on the highway and it started again. I'd happily by someone a case of their favorite beverage for helping me figure this out!

krawler-N-tow

Forgot to mention, no codes.

KATOOM

Beverages.....?

Is your cruise vacuum or electronic controlled? If you have a vacuum pod sitting under the drivers side battery then its vacuum. If you have the plug on the APPS sensor then its likely electronic.

krawler-N-tow

Electronic as all '02 models are, controlled by the ecm.

KATOOM

Actually thats not accurate. There are plenty of vacuum cruise control '02's and the ECM controls no matter which one. As I mentioned before, no one seems to know what trucks came with what nor why. Some think it has something to do with the tranny and some think it has something to do with it being an SO or HO. Either way..... Knowing what the OP has may help.

krawler-N-tow

I've probably read on more than 4 boards and 30 pages of open ended threads of this issue on 2002 models. Working 12hr shifts I don't have time to go waste time at a shop trying to figure it out. The guy that made my apps says it isn't it due to the cruise going through the ecm. I'm leaning towards replacing the ecm but that's just a $500 gamble I'd have to make by tomorrow for it to get here before I drive across country.

KATOOM

Replacing the very expensive ECM would be my last approach too..... There are some key things to look for if the ECM is the problem.

If you have the vacuum controlled cruise then I'd suggest looking for any potential vacuum leaks. Maybe even throw a vacuum test gauge on there and make sure you're pulling anywhere between 20-25.

Aside from that, its very important to understand that these 2nd gen 24 valve VP trucks are completely electronically controlled and monitored. So that said, if there is ANY voltage/amperage problems causing the system to run out of parameters then it will result in phantom issues having you chasing your tail.

What you need to be sure of is looking to make sure both batteries are in perfect condition and the same age. Also, if you live were road salts are used and corrosion is an issue then make sure there's no major cables, connections, or grounds are compromised by corrosion and that they're tight and making solid connections. Many a times someone has found a loose battery cable or loose ground.

Lastly, the alternator must be supplying the correct voltage and.....very important.....it must NOT be making excessive AC noise otherwise it will mess with the other sensitive electrical devices like the APPS or the automatic tranny solenoids. Potentially even damaging the VP's PSG over time.

I know thats quite a list but this is what you get with internet diagnostics.

krawler-N-tow

It's not vacuum controlled and check on all the things you mentioned. I bought this truck new, with 11 miles on it after the test drive. It has 211k on it now and has been well maintained. Not to say something might not have gotten corroded or such but this is a garage kept truck, zero known rust issues. So I could waste a lot of time checking grounds that I don't have right now. I'll check the alternator, battery's are good.

KATOOM

Its a laundry list of items that I have to state since I can only assume most people asking are not like you.....

But yes, check the alternator output and AC noise.

SIXSLUG

211K miles......How about the clockspring?Are your radio controls working? If an SLT Laramie Plus?

Electrical gremlins can be frustrating as all !!!!

I just realized my truck is 3 honking because of door sag...the hinges are worn and allowing the button to not fully depress, duct tape and a bottle cap til I have time to R&R....I feel your 12 hour days K-n-Tow!!

KATOOM

I've heard about this "3 honk" thingy for years and this is the first I've heard of anyone discovering what the cause is.....
That said, I NEVER EVER start or shut off the engine with the doors open. Anyone who opens the doors before the engine is off will get the "look" until they shut it again.