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Hi everyone, I have an 88 F150 that has the 300-6, with auto transmission, 2wd. I'm having some issues with it idling and stalling.
Today I replaced the IAC and that seemed to help but it still didn't seem to idle right. It was still stalling when changing gears. Drove fine once it was in gear and moving.
So I then replaced the throttle position sensor to see if that would help and keep it from stalling. No dice, now it stalls when in gear and moving. I now see me putting the old TPS back in.
I plan on running a third of a can of Seafoam through. Aside from this, can anyone give me an idea on what might work next? Any help would be greatly appreciated, thanks.
I would suspect a vacuum leak or fuel pressure issue. It's quicker to just replace all of the small diameter vacuum lines than it is to test them, they can be picked up for less than $20 at an auto part store (22ft 4mm line + one 4-way vacuum tee) but I recommend going with this (http://www.siliconeintakes.com/silic...686d47fdf65361) if you have the time to wait on shipping as they will outlast the truck. You can get a fuel pressure tester from any auto parts store through their loaner tool program.
Was the new tps a motorcraft part? if not then that could definitely be your issue with the new one. Also did you test it for proper voltage? .9-.97v closed throttle, 5v WOT, smooth increase as you open it up.
Also a good idea to clean the TB blades (edge of blades and side of TB were they meet) with some TB cleaner, a tooth brush, and a rag.
No. The TPS was not motorcraft. It was whatever Advance Auto had in stock. It didn't do this before I switched it so I'm going to put the old one back on and see if it helps. Before, it at least drove. I also read somewhere that there's a certain way to put those on. I did not test the TPS, I don't have the tools to do it and I don't know electrical.
I was going to look into the vacuum lines as well, just haven't quite gotten there yet. I will also look into testing the fuel pressure. I wonder if they could test for me instead of having to buy the tool and then return it..
When you get the FP tester (from oreilly's anyway) it comes with a multimeter so you can test the TPS. The ones in both of the kits at my local one have never even been used, still in the plastic wrap. Depending on where you go they might do it for you, don't know how the guys are at AA but the ones at my local oreilly's will usually help you if you don't know what you're doing.
As for installing the new TPS you pretty much just have to put it on the same way it came off, I've seen some advice saying to rotate it 180* but when I did mine last week (engine surging, throwing a 123 code-TPS voltage) I just remove the TB and swapped the TPS with the new motorcraft one, keeping the wires pointed in the same direction. Thought I would have to do some adjusting but it was good to go on the first try.
As for the FP tester, I'll definitely look into it. I messed with the TPS again and did the rotating method and it didn't stall out on me. I do have a check engine light now (didn't before) but it'll stay running. In combination with the new IAC valve, the truck is running better but there's still some surging while sitting at idle. Starts up somewhat decent, but still needs a little gas at times right at fire up. Gonna see if a guy I work with will help run some Seafoam tomorrow. I already put some in the gas tank and filled her up. I feel that should help a little as well.
On an unrelated note, I need to replace the oil pan gasket. The gasket itself is flapping outside of the oil pan. The whole driver side of the motor is covered in oil. I didn't notice somehow when I bought it. But, should be a simple fix.
Pull your codes, I'm guessing the CEL is going to be something TPS related.
I've been holding off on doing my OP gasket because I didn't want to put the time into it. The truck only looses about a quart of oil every 5/6 weeks so to me it isn't worth it right now, hell some trucks burn more oil than that, the only downside is she marks her territory, just a couple of drops at a time but it prevents me from parking in a lot of customers driveways. Make sure you clean the entire area very well, once you think it's clean enough clean it again, making sure to get between the crossmember and the pan the best you can. If you aren't planning on lifting the motor up then you will be fishing the gasket over/around the pan, the area needs to be free of gunk that could cause issues with sealing the pan to the crankcase. Have fun and let me know how it went.
Little update, been extremely busy so I haven't been able to narrow down what was causing the truck to not run the best. Although, I did get the fuel filter changed and I also found that my air filter was caked in oil.
That being said, my issue my be from that...I found that the vent tube the runs from the valve cover to the air box wasnt attached to anything. My stepdad said it should be connected to the air box but no dice. Is there supposed to be a valve of some sort there, or just a 90* elbow like it already has? Also, there was a smaller filter-like piece right there, what would I look that up as to get a new one?
Also, we got the oil pan gasket changed and the front shocks as well, and called it quits. That gasket took every bit of 4 hours, with the motor raised. Didn't fill her up though, gonna get a cheap oil and fill it and run it with that for 2 weeks to get any residual dirt and gunk out and then fill it with my regular high mileage oil.
I think it is called the breather element or something like that. It is a small filter type thingy with a barb that sticks out of the air box. That connects to the hose that runs to your valve cover.
You should pull you PCV valve and make sure it rattles when you shake it, when the PCV is bad it can force excessive oil out the crankcase breather line. If it does need replaced (or if it's not a motorcraft PCV valve-rattling or not) use ONLY a motorcraft PCV valve. There are very few parts that must be motorcraft for proper functioning, but if they are different brand you will end up having nothing but problems with/from them.
08-16-2015, 12:29 AM
Idle and stalling issues
