Backfires can be minor or major, it all depends. A backfire is a backfire, I have learned. I'd say that you are on the right track with your gaskets, but personally I wouldn't go changing sensors unless you were throwing codes.

Think of it this way: suppose your truck was overheating, and your dashboard thermometer was indicating that your temp was in the red. It is a sensor, so you go ahead and replace it. Is that likely to fix your overheating problem? Now it is possible that the only thing wrong with your truck was your temp gauge, but most likely you have to fix whatever was causing your sensor to act that way, ie a clogged rad, low fluid, etc.


Same with the MAP, TPS, etc. Even if you were throwing codes, my suggestion would be to investigate the system that the sensor was regulating, and try to iron out whatever is causing it to act that way. Since you are not throwing any codes, I would start with the gaskets, then go to new vac lines (if they are damaged or cracked, no need to replace what isnt bad), and go from there. More often than not all a vacuum line needs to make a good seal is to chop off the ends at about an inch, press them back onto their nipple, and tighten back up the hose clamp.

However, all that being said, I will not shirk at admitting that out of frustration I have in my day gone to the junkyard, stolen all of the sensors I could steal, and just replace them one by one hoping for improvement. I'm no ASE mechanic, just a guy with a shadetree.

 

Bend your vacuum lines and look for cracks. Retorque your intake bolts. Aluminum is more sensitive to temperatures than pig iron and will stretch and shrink more. As far as your cat being gutted, I would think you would pull a code from the front bank sensor, but oh well. It would be wise to know what your spark plugs looked like (ie brown, blue green, shiny, oily, carbon tracked etc.) all indicating different things. Check your knock sensor (if these have one), and check your coolant temp sensor (because your problems are before op temps). Just my .02

 

the spark plugs i took out were like 6 months old and they looked as clean as the new ones i put back in

 

wheres the coolant temp sensor located???

 

It is jammed into the block of your engine somewhere, mine is by the thermostat. Your manual could probably clue you in on this one. Not a bad idea, as your computer reads how hot or cold your engine is from this sensor, and adjusts the air/gas ratio correspondingly, making it richer or leaner.

 

i would look towards the ignition coil...that could be the problem unless you replaced that...but the coolant temp sensor you are looking for is located behind the ac compressor down in the dark crevice of the motor, its a pain to replace if you don't have the right tools. the one that the gauge on the dash reads is behind the alt. you can reach this one from the passenger fender

 

They are next to the thermostat housing on both sides. There are 2. One 1 wire for the gauge. One 2 wire for the computer.

 

I have an 89 Dodge Dakota 3.9. About two and a half months ago the temp got down to around sixty degrees and my truck started backfiring throught the throttle body, surging, and dying. When the weather was good it ran OK. I replaced several sensors, EGR coolant temp, Map sensor to no avail. I took the trottle body apart and cleaned, all the vacuum ports were filthy. The truck ran much better and no longer had a problem with outside temp in the fifties. Well this week the temp dropped into the twenties and my problem came back. I rerouted the vacuum for the fuel pressure regulator to a vacuum port on the intake manifold yesterday and plugged the port on the throttle body. Drove the truck to work today and it was cold out and the truck ran good, no backfire and no dying. I replaced the fuel pressure regulator today and moved the vacuum back to the original port on the throttle body and it ran great. It is twenty five outside and I just went out and started the truck and it idled good. Just a thought. Your problem sounds very close to what I was experiencing. Hope this helps.

 

i dont know if this helps u guys any but i noticed that when i try putting it in cruise control it holds for like a sec or 2 then turns off auto, wont stay on

 

I had a similar issue on a dodge I owned... the mechanic resolved the issue... faulty computer. It started throwing the fuel and firing off till it eventual would not run anymore. Started off with little hick ups, as time went on, it led to once massive backfire one day, probably
blew the baffles right out of the muffler. And the lady jogging with her dog probably had to go home to change her underwear haha.
Not saying that this is your problem, just a thought.

I would highly recommend testing all the sensors and parts you can before buying them unless you want to replace everything you run into.

As for the cruise control, Im just guessing but Im wondering if you have a vacuum leak in your hose. The line loses vacuum and kicks out the cruise possibly?