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Discussion Starter · #1 ·
Hi all hope you can give me some help with a strange idle issue I'm having with my 98 Ram 1500, 5.2 auto, 2wd. When I start the engine from cold it runs just fine, but after it has warmed up and I shut it off to run some quick stops to pick up things, I restart and it idles real rough. It almost dies unless I catch it in time and it smells real rich. It doesn't matter how many times I restart it as long as it is warm it do this rough idle. When I get going up to speed it is ok, but in traffic it is difficult to keep it running. I have changed the Idle air mixture sensor on the back of the intake, the intake gasket has been fixed and also the map sensor. I thinking maybe o2 sensors or? Thanks in advance.
 

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O2 sensor for sure. I think you have 2 of them. Might as well replace both. And this would only be an upstream sensor (before the cat) not a downstream if you even have any.
 

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Discussion Starter · #3 ·
idle

Thanks for the reply. There are two of them, upstream and downstream, I will replace both for sure.
 

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If the O2 sensors don't fix it try your water temp sensor. I had a 1990 Ram van with the 5.2 and had the same problem. Took it to the dealer and they said the temp sensor had reversed polarity causing the engine to ask for more gas as it got hotter.
 

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Discussion Starter · #5 ·
Idle

Thanks for the input. Those dammed sensors again. Thanks for your years of service in the Air Force.
 

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Discussion Starter · #7 ·
Idle

Well I have replaced all the suggested sensors, the engine idles a little better but still does the rough stuff after it warms up. I am at my wits end about what it could be. When the idle is doing its thing, it smells rich like its getting to much fuel. Thanks for your help.
 

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Discussion Starter · #10 ·
Idle

The replaced sensors; Map, I/A, TPS, O2 sensor, Coolant Sensor, Air intake sensor, Intake manifold gasket. The Cap, Rotor, Plugs and wires and an Accel coil about 6 months ago. We don't drive that much maybe 50mi a week. I don't haul or pull anything heavy. Thats all I can think of right now. Thanks for your help.
 

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The replaced sensors; Map, I/A, TPS, O2 sensor, Coolant Sensor, Air intake sensor, Intake manifold gasket. The Cap, Rotor, Plugs and wires and an Accel coil about 6 months ago. We don't drive that much maybe 50mi a week. I don't haul or pull anything heavy. Thats all I can think of right now. Thanks for your help.

Well it looks like you covered all the sensors plus other things. Don't know where to tell you to go next. Might be time for a trip to the dealer and let them tell you what is wrong then fix it yourself.
 

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Cap, Rotor, Plugs and wires and an Accel coil

I would get rid of the Accel coil! I had one on my truck and it left me stranded. It was only about two years old. Have read others had similar issues with them. When all these parts where replaced was the pcm reset? You need to let the pcm "relearn" all the new parts. Also it does matter what brand parts you use. Stay away from anything BWD or house brands. I have seen some people go threw 4-5 of the IAC's before getting one that works correctly. You might want to check the fuel pressure when it's up to temp and starts it's running rough to see if you have a stable pressure. When you replaced the IAC did you clean out the throttle body? Carbon builds up in the ports and can cause issues if it's not clean.
 

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Discussion Starter · #13 ·
idle

Thanks for the thoughts. I try to get good parts by using NAPA's good line. I did have a good engine man use a scope on this, and he replaced some of the parts that were suspect. He doesn't have a high dollar scope, but I guess it is ok for his shop. I'm 75yro and on a fixed income so I have to be careful what I spend. This Dodge engine sits so far back in the frame it is hard for me to reach the distrib so I take it to him for that kind of work. He builds wicked race engines, I have used him for about 8 years. We live in BFE so there is not very many shops to choose from. I have been to the the Dodge dealer in the next town, they bleed you just to scan your truck. Don't you have to use a special kind of cleaner for the Throttle Body? The only problem with taking the truck to my friend's shop is it takes so long to get in and the get it back. He knows our money situation and gives me a break by doing the work when he has time between his other jobs. I do what I know I can without getting into trouble both knowledge wise and physically. I have been working around engines all my life both as a living and as a hobby, but things were not as complicated then. I still restore old Garden Tractors. Anyway thanks for hearing me out and all the ideas.
 

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If you can remove the TB yourself it's not hard to clean. There are more parts on a carburetor. You can try removing the IAC and take a look in the back(use a mirror) to see what it looks like.
 
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