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Discussion Starter · #1 ·
I just finished putting an '01 rodeo engine in my '02 rodeo sport. It drove great for the weekend. Then, this week I took it over the pass to Fort Collins. climbing the pass, The car downshifted into second and would not go above 3200 rpms and I was stuck there for the entire climb. Also, the rest of the drive to Walden, every time it downshifted for power, it had no power until the rpms got down to around 3200 again. I stopped briefly in Walden, and then when I started it, the idle was low and lugged for a few seconds before popping back up. Then it drove fine the rest of the way to Ft. Collins. The next morning when I started it, it stalled the first two starts and lugged on the third, but eventually idled back up to normal and drove with a jumpy idle until it warmed up. I got it home (with the same power issues occurring on the drive back) and did some research. It has not flashed the check engine light even once, and I have not yet tried to put a code reader on it.
Will it even throw codes w/o a check engine light?

I did replace the TPS thinking that might be it. Checked the spark plugs...they are perfect. Cant hear a misfire. I'm not sure what would be causing this without the CEL. Any help would be greatly appreciated. Thanks!
 

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OBDII does not check fuel pressure, so you may have a fuel delivery problem. Check the fuel pressure with gauge, it should be about 36 PSI a idle. The CEL will be illuminated if a DTC is stored.
 

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Discussion Starter · #4 ·
so, I guess the bulb is out on the CEL cause It pulled 3 codes; P1311, and P1312, which are ion sensor module codes. Turns out the ignition ion sensor computer on top of the intake manifold was bad. I think it probably got exposed to the elements before I got the new engine. So I replaced the ion sensor module with the one off the old engine, and it seems to be running fine. I will hook it up to another code reader to make sure they are gone.

Also it is throwing an 02 sensor code. Are there only the two 02 sensors before and after the Cat? or are there more?
 

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There are 4 O2 sensors total, 1 before each cat and 1 after. The upstream ones control air/fuel ratio, the others monitor catalyst performance.
 

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Discussion Starter · #7 ·
ok, New update. 02 sensor replaced and ISM replaced. Codes are gone. Went and cleaned the EGR tube ( which was beyond nasty) and the exhaust EGR tube. Cleaned Throttle body and replace TB gasket as well as EGR gasket. Truck is def. running better, However, the idle is still lugging...very occasionally, and there is an occasion whine that sounds exactly like this one:
. My only thoughts are either IMG leak? Exhaust Man gasket leak? wiring issue? or vaccume leak?

A little lost on this one, it seems this is a rare sound.
 

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Discussion Starter · #9 ·
I was just driving around and found that if i am on the accelerator, no matter how lightly, the sound stops. But when i take my foot off it comes right back. Thinking maybe bad TB?
 

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I've only found 2 posts in google search that deals with it and one was on here and was the guy that did that video. Neither had a solution though. The guy with the trooper posted that it just went away one day and hadnt come back. One suggestion in his post was an identical sound on a ford that turned out to be a bad connection on the TB actuator connector.

viewtopic.php?p=205240
 

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Discussion Starter · #11 ·
So, I switched the TPS last night, and nothing changed. So Today I switched the whole throttle body and it is now running great....however, I didn't get to take it for a long test drive. But did let it idle and rev'd it up quite a bit and the sound seems to be gone, as well the engine sounds like new! I am thinking it was the Throttle Acutator, but will know for sure tomorrow
 

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Discussion Starter · #12 ·
So the throttle noise is fixed! it was the actuator after all and luckily I pulled to TB off the old engine. The rough idle seems to be fixed as well. HOWEVER, the lack of power on acceleration is still present and driving me crazy. I ordered a new ERG valve and PCV valve as well, I ordered the specific denso spark plugs. Any other ideas??

Also, there is a solenoid w/2 vacuum hoses coming off of it right next to the TB and I'm not sure what it's called...anyone know its technical name? thanks again for everyone's input
 

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Discussion Starter · #13 ·
Put the denso plugs in and got the codes read. Still kicking out a p1311 code but no p1312. So new plugs and ism, so not sure what would make it kick out the p1311 code
 

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The solenoid with the 2 hoses is the fuel canister purge valve. P1311 is Ion Sensing Module SEC line 2 circuit fault. It is the same as P1312 but on the opposite cylinder bank. P1311 can be set if the cam timing on the right hand cylinder bank is incorrect. Run a compression test, if the bank is low it is out of time.
 

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Did you replace the timing belt?
 

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Discussion Starter · #16 ·
Buster, i did get the engine compression tested at a local shop after install. So unless thay messesd it up...

Medic i didn't change the timing belt cause it looked good along with the components.

Also the po155 code came back yesterday and turned out to be a loose connection on the o2 sensor (probably my fault). But could that also cause the p1311 code?
 

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Sometimes a problem with one sensor can throw a code for a different sensor depending on how its effecting it.

When you changed the plugs did you get the coil packs back on in the right order? #6 has a shorter boot then the others so if you get them mixed up you can get a misfire code.
 
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