Guys,

I have a '99 Ram 1500, 2wd - auto. It has the 360 (5.9L) engine with 33,000 miles.

2 weeks ago I began to get an odd "surge" while at hiway speeds. Almost like the tranny was not locking out, and was trying to down shift.

The surge was not jerky at all, and only "upwards". By that I mean the RPMs would slide up 2-300 rpms while at a steady speed. I first noticed it on the Interstate with the cruise set at 75mph. It would kick the cruise off.

I had the tranny flushed (with a machine) and the tranny fluid replaced-at 24,000 miles. There has been very little towing done with this vehicle, infact I do not even have a receiver hitch! I do not think it is a tranny issue, but maybe you guys know ... Additionally, at 70, I turned the Overdrive OFF, and set the cruise ... I still got the surge.

I had a similar problem with a previous vehicle and it was an EGR valve issue. I do not believe my vehicle has an EGR valve ...

So I checked what I could check, and then took it to the Dodge Dealer/shop. They diagnosed the fuel position sensor, replaced it, and while I was there I had them do a tune-up (because I am lazy) ... they flushed the injectors, new plugs, etc.

Well, I drove the vehicle for 3 days, but not on the hiway. So today I got on the way to work, and the mystery surge was back ....................

Any ideas?

 

Fuel position sensor? [&:] Did they maybe replace the throttle position sensor?

 

Idle Air Control Valve. That is on the other side of the throtle position sensor, but that should change the speed. They do have an EGR and that could be part of the problem. All three of these things can build up with carbon and stick. Being that your truck only has 33,000 and is now 8rys it might just need to be driven hard. Maybe it is already I don't know however, I do know that they don't like to sit around thats when gunk and crap start to build up. Good Luck and Drive it like you stole it.

 

Actually, they don't have an EGR valve. Only the Diesels had them in the later years I think they took them off the gassers after the 96 model year. I'm not even sure if the Diesels had them after 1999. I don't see anything about them in the service manual.

The IAC could be part of the problem though.

 

Ahhh ... 10-4 ... It was the throttle Position Sensor I had replaced ...

Ok, so I have been given advice to (basically) Drive the HELL out of it foew a while .... I like that! Alot!


Would there be any other symptoms if the Idle Air Control Valve was going bad?

 

Not necissarily going bad. Might just be dirty. It would hesitate when you start out from a stop. It would also hesitate when you brake for long periods of time.

 

Check with the shop that did the work. If they replaced the throttle position sensor it was a pretty good guess, but obviously didnt solve the problem. check and clean the throttle body and idle valve then check fuel pressure, if the regulators going bad you may only notice it at cruise speeds (2000-2500 rpm) good luck

 

I've had the same problem with mine, under the same cirumstances, cruisin at 75 on the highway, cruise control on. My truck is a '00 1500 318 2wd with over 93,000 miles on it, and i've driven it hard. I'm gonna mess with what has been suggested and see if it helps me.

 

Try the tps first. it takes 10 mins to install and set up, costs $30.00 and even if it wont cure the problem, it will restore some throttle response. While your putting that in, clean the throttle body and iac, this will help idle and off idle response and its free. Fuel pump might be possible, but I didnt replace them in either of my trucks until 145k. Good luck

 

Well thanks a bunch guys ... It looks like I found the right forum!

I have replaced the Throttle Position Sensor. Had the entire fuel system/injectors flushed out, cleaned the throttle body, and put in a fresh tank of gas ...

I am gonna mash down the gas (where it is safe) a few times and see what happens ... I am also going to find-pull-clean the Air Idle Control valve.

I dunno .... At least my cruise quick kicking off since the TPS has been replaced ...

Thanks for all you have done/said, I appreciate it ...