Lvnvgt

Ok guys im new to the site and to the 4.6. I bought my 02 gt about 2mo ago. It did have a bad iac which I replaced but it feels like its holding back on me. It has 90k on the clock and 100% stock. ive done the fuel filter, fpr, pcv, bought new plugs since im getting to the 100k mark, clean the maf with crc, cleaned the throttle boddy and today I changed the air filter. After changing the air filter I forgot to plug the maf back in. it in no way changed the way the car ran but I finally got the check eng light. B4 I changed the iac the p1507 code was all I got for iac issue. I havent installed the plugs yet because im prety sure when I unplugged the maf it shouldve ran like crap or put it into limp mode so I think I have a bad maf.ne1 have any advise it would be greatly apreciated. Thanx

Lvnvgt

Also sorry if its in the wrong section and I have been using the search to try and find something simular b4 I posted here. Thanx guys

Lvnvgt

Hello? Lol

ryanm

I've never run my 98 GT without the MAF plugged up, but I can tell you that when I changed my plugs around 100k the car truly came back to life. They claim that plugs these days last around 100k miles, but I have my doubts. I would also change your plug wires if you see any signs of arcing on the wires. Did you get a high-flow air filter (K&N)? The standard cone filter pales in comparison to a good high-flow filter. I think your 02 also came with a "silencer" attached after the air filter housing. It looks like a rubber cone and it should be removed for better air flow. You're on the right track with the things that you have done. Change your plugs and wires if needed, reconnect the MAF, and see if you still feel that it is holding back on you.

I hope you used MAF specific cleaner on the MAF. If not, then you might have fried it. I've heard horror stories about people using throttle body cleaner on the MAF and having to replace the unit. Somewhere around $200-$300 for a new MAF...I think.

Lvnvgt

Thanx for the reply ryanm.. I did use the crc maf cleaner on the maf. Im going to school for elec engineering and thats 1 thing I know to use. I just bought a reg stp air filter cause once I have the 100k service stuff done and its running 100% I want to start upgrading. I want ething to be the way it should b4 I start throwing parts at it and end up with a mess. I plan on a cai, the stc chip and a simple cat back. I dont want to do to much to an eng with almost 100k on it. I know it can handle it but ide rather build a fresh motor or move up to the dohc later. Since my car started this lil hissy fit its also been shifting weird. Kinda shifts hard and when I hit the gas from a stop it just doesnt have the go it use to. It doesnt even chirp the tires really. I did test the maf with a volt meter and it does seem to be workibg so im guessing the tps is the next thing to look at after plugs. Im still not getting ne codes so I would imagine the o2 are working correctly. The thing I hope isnt wrong is clogged cats... Kinda has the symtoms of that as wel

Lackey'sGT

Did you unhook the battery if not I'd do that and leave it unplugged for about 10 minutes. It gives it time to clear the computer in the car so that when you go to drive it it relearns everything.

It should have changed the way the motor runs when the MAF was unplugged. It should have made it bog out when you try to give it some gas and run rough. Resetting the computer might make the problem worse which would most likely mean you do have a bad MAF because the computer before was trying to stay running with the bad MAF over time. I'd try this if nothing changes then I may be wrong it’s worth a shot to see if anything changes.

On my car (2000 GT) I cleaned my engine and took off the cai and when I reinstalled it I forgot to hook the MAF back up and I could barely drive the car while it was unplugged.

Lvnvgt

Thanx lackey, I did reset the comp after changing e part and after I forgot to plug the maf in. yesterday I ecen unplugfed it while running and this time it sputtered on me so I tested wire d. I had sum1 rev from idle to 1500 and then 2500rpms while I tested for voltage. I was getting about 1.4 at 1500 and a lil over 1.8 at 2500. It didnt fluctuate at idle either so w/o actually testing msf signal through a tuner or programmer i would assume its functioning correctly. Then again.. I couldnt test under load either w/o a programmer. I cant find any vac leaks either.. Might have to actually take it to ford and shell out the cash for a diagnostic. Could be a cop missibg but slight enough the pcm isnt throwing a code. This is 1 wild goose chase let me tell u haha.

Lvnvgt

The thing with the way the trans is shifting is what really scares me.. Def cant afford a new trans at the moment

Lackey'sGT

Yeah I know how you feel there I’m also a college student finishing my senior year for Design Engineering. Is the car straight miss firing? Can you hear it at ideal? It’s a common problem and sadly there could be a lot of different solutions, check the current on the injectors and COP's and see if one is different than the others. Also a lot of people think they have clogged cats it’s not very likely especially since you only have 90,000 miles. See how much it would be to have Ford look at it but idk if they will be able to give you an exact answer. I may have just missed it but is the car an automatic?

Lvnvgt

Yeah it does suck cause I really love the car. Ive always played with big blocks and forced inducted cars b4 but I really like the mustang. It is an auto and the 4r70w which I know has a vibrationissue when in full lock.it literally is acting like my 454 with the th400 and the vac modulator took a dump. It does have a slight miss and really only sputters off the line once in a while. It just doesnt have the umph it had b4.. Its way hard to explain lol. Its almost like it gets confused and goes back and forth running on the signal between the maf and tps untill it just goes into limp mode. My srt use to do that to me all the time and it ended up being the coil causeing the fuss. I know the problem im having is probly so simple that im over looking it lol. Do u think maybe iat sensor? I do live in vegas and it does act up more when its about 110 outside lol