Part throttle hesitation

[masho95]

Ok I posted something on this before and was hoping to get some more input on this. Here's the deal, when applying part throttle the cars won't accelerate like it's supposed to for a second sometimes a few then with the pedal in the same position it all the sudden starts to accelerate (like you hit the gas, but even though the pedal is in the same position).

I was thinking TPS dead spot or something but it doesn't do it every single time, it's kinda random. I checked the TPS output voltages anyways and there isn't any dead spots on it. About .86V at idle now and 4.5V at WOT.

So I finally got around to changing the spark plug wires with OEM Motorcraft wires and found oil in the rear spark plug wells. Replaced the rear valve cover seal and spark plug tube seals, installed new wires and all new plugs. After all this the car did the same thing sometime within a week after I did all the work.

The MAF has been cleaned a few times before also. So what else would cause a lack of acceleration at part throttle? I believe it's almost time to check the conical K&N air filter that sits in the fender well, perhaps I'll take a look at that tomorrow, but could that have any effect on what's going on??
Anything else to check?

 

[Slo-Sho]

You would be surprised how quickly the fuel filter can accumulate foreign particulate especially from an almost decade old car.

 

[Hack]

You say that after installing the new plug wires,cam cover gaskets, etc it stopped, right? Have you checked those rear plugs again since it started up again? Maybe they are still leaking and it took a week or so to accumulate enough to cause the problem.

Also, when was the last time the crank position sensor replaced last? I had all kinds of weird issues that are not normally associated with a failing or aged CPS, but they were corrected by replacing it. These included a rough idle and part throttle hesitation, among others.

Its not much, but thats all I've got.

 

[masho95]

You say that after installing the new plug wires,cam cover gaskets, etc it stopped, right? Have you checked those rear plugs again since it started up again? Maybe they are still leaking and it took a week or so to accumulate enough to cause the problem.

Also, when was the last time the crank position sensor replaced last? I had all kinds of weird issues that are not normally associated with a failing or aged CPS, but they were corrected by replacing it. These included a rough idle and part throttle hesitation, among others.

Its not much, but thats all I've got.

No after installing all the new parts it still had the problem. Happened again the same week I changed all those things. Haven't checked the rear plugs again but I'm assuming with all new seals they it isn't leaking. Last time the crank sensor was changed was probably a few years ago, and I'm going to rule that one out for now, but I'll keep it in the back of my head, thanks.

 

[Rockledge]

I'll throw this into the ***:

http://www.shotimes.com/php-bin/mod...le=article&mode=thread&order=0&thold=0&sid=79

 

[masho95]

I'll throw this into the ***:

http://www.shotimes.com/php-bin/mod...le=article&mode=thread&order=0&thold=0&sid=79

Thanks, I'll have to take a look at that. The IAB was changed out 4 years ago (7/14/00) so who knows what's going on with it.

BTW I checked my ail filter and it was a little nasty, so it's getting cleaned and re-oiled before getting put back. While under the wheel well I also noticed something that wasn't good. The bolts through the tranny mount that go into the subframe were coming out! The left one was almost half way out and the other way almost an inch out! Those got tightened down nice and tight. I must have forgotten to torque them last time I had the tranny out. So we'll see how the air filter cleaning goes and I'll have to check out that IAB valve.

 

[morebhp]

I ditto what Slo-Sho said. I had the same experience as you and made the same efforts to remedy the problem. I had given up. Then one day I replaced the fuel filter just because it was old. Bling! The hesitation stopped, and stayed stopped. It's worth a try.

 

[SHO_Driver]

Did you try driving with the MAF unplugged? What about putting in the stock airbox?

 

[masho95]

Did you try driving with the MAF unplugged? What about putting in the stock airbox?

No disconnect the MAF doesn't make the car run good. Stock airbox might be an idea, but I no longer have my K&N filter for it. It got donated to my buddies 89. I did pull out the conical K&N today, cleaned it and re-oiled it.

After cleaning the air filter I went to start to check out the IAB valve. The lower bolt was slightly loose. I ran out of time to pull it completely apart so I just tightened up the lower bolt and made sure everything was as it was supposed to be. So between the clean air filter and tightened up IAB hopefully everything will be back to normal. I'll have to drive it for a week or two and see how things go.