The truck is 93 4.0L v6 5-spd 180,000k, about two weeks ago put new plugs in and things ran fine. A few days ago the truck started and acted like a Harley-Davidson, sputtering and reving from 700rpms to 1200 and eventually it will idle and run down the road just fine. However somethin got screwed when back pressure in the fuel or emissions shot off some rubber caps on the vacuum tree on back of top manifold where the 3 or so vacuum lines hook up to it, which have now been capped back on. I changed the fuel filter and put new plug wires on it. The Idle Air Control valve was removed and attempted to be cleaned amd lubricated/ that thing was very carbonated and such. The (MAF) was removed and cleaned with carb cleaner since i run a K&N, hope that oily K&N did not make my truck sick, oh well. There is an odor of stinky exhaust/etc so somfin aint right. I need to use my Haynes and voltmeter to check some of that electrical stuff connections, etc. I bought AAA plus coverage which is the best thing i can do for now, ha, ha. I'm gettin a CEL coming off and on so maybe Autozone can hook me up with some codes. I removed and tinkered with the FPR or EGR and it seemed crusty too, so who knows what it is, maybe a bad fuel pump since my fuel level gauge is broke, thanks for any help!!

 

wish someone could help me out here, but oh well, think i will invest in a scanner since my 94 civic is high mileage too in case it needs TLC from a check engine light. Peace Out!!!!!!!!!!!!!!

 

i am sure someone can post to help...

this thread just got overlooked...

 

First I don't think carb cleaner was the right thing to use although i could be wrong about that.

Seond I hear those IACs just go bad sometime, and that you can't always clean and lube them.

Wish you luck on getting everything running right though.

 

maybe when the truck gets scanned it will help but with my research it does seem like the iAC causes that wave of slight up and down rpm's at idle. In hinsight i shoulda used electric cleaner instead of carb cleaner. The truck runs like a champ on the highway but starting is gettin worse. I did take apart the Fuel Pressure Regulator and the vacuum line goin to that 4 inlet vacuum tree is getting bits of gas shot into that vacuum line from the FPR. That does not seem normal so, who knows i'll keep tryin. With 180,000 miles i would not mind puttin 150 bucks in a remanufactured MAF, IAC, and FPR! But I when my tax comes back I really want to upgrade from 31.10.50's to 32.11.50's, i think they would look so sharp and my BFG's are gettin low on tread, so as usual i will pay for aesthitics before fixin the motor, lol, i'll call AAA, thanks all for your help; i can't believe those MAF's go bad so often and the IAC. My truck still looks better than a Tacoma even if it has crappy gas mileage and drives like a tank, ha ha

 

go to ace hardware and look for stuff called seafoam engine cleaner

-in your driveway start your truck and open the hood
-take out the vacuum line frome your brake booster
-slowly with out stalling the engine pour the seafoam into the line
-when the bottle is out turn off the truck
-put the line back
-wait for 5+ minutes
-turn on the engine again and rev at 2500 until the exhaust is back to normal

worked great on my truck

 

when that happened to me it turned out to be my tps

 

Hey thanks for the suggestions. I been thinkin of usin that seafoam to clean out the top of the motor, but I guess I need to wait till i'm ready to change my oil since it seems the oil is supposed to be changed after using SEAFOAM on the throttle upper manifold cleaning; but it could be my TPS like McerWing's truck. I am still baffled by the Fuel Pressure Regulator spitting gas into the vaccum line goin to that vacuum tree thingy.

 

Got some Seafoam and added almost a whole can to the brake booster vacuum tree intake. That stuff is the shizz-nitt, smoked pretty bad but my truck cranks up like a champ. It still has a miss, likely IAC or MAF, but anything that has a motor is gonna get a shot of Seafom in my garage!!!!!!!!!!

 

BAMM, i got er-fixed, IT was my FUEL PRESSURE REGULATOR that had gone bad. It was spittin out gas into the vacuum line which likely had caused some other parts to be possibly damaged but likely not. Paid 102 bucks for the new FPR, and now the truck runs awesome. Now, I am unsure of what the idle should be set at RPM's when warm since the idle screw was adjusted over the past few weeks. I think right now it idles at about 1,100 RPM's and seems like that is kinda high. Peace and check yo regulators for gas gettin into the vac line!!!!!!!!!!!!!!!!

 

my cold idle is ABOUT 1000-1100, warm is about 500-650. that is ABOUT .. maybe bob will chime in.

 

(without reading this whole post)

i had the rough idle problem... and sometimes its wouldnt start at all.. i had to keep my foot on the gas for about 1-2 mins.. anyhow tonight i replaced my IAC , i got it for 56.51 out the door at the local dealership, and sofar it seems good... we will see tomorrow morning...

 

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