94 f150 5.0 stumble around 1500 RPM
#1
94 f150 5.0 stumble around 1500 RPM
New guy here with a problem. Any help would be appreciated. My 94 F150 has a sort of stumble at around 1500 RPM. I had a reman engine installed, the old one used oil and just wasn't performing good. The stumble was there before the engine change and I actually thought it was a tire. I was wrong. I have no codes or CEL. I have replaced almost everything except the MAF and O2 sensor. It has a new PCM, Distributor, plugs and wires, EGR and regulator and EGR sensor, TP sensor, injectors, and coolant sensor. I don't have a vacuum leak. I can duplicate the problem at idle by bringing up the revs to about 1500 and the engine shakes. I have the EGR blocked off at the moment but it gets alot worse if I hook up the EGR valve. Is this a wiring issue? I really want to get this fixed, this is my main daily driver. I want to restore this truck but don't want to go any further until this problem is fixed. Help!
#2
you don,t suppose the timing is off or a valve sticking ? check the timing with a timing light ! also hook up a vacuum tester to the engine to see if there are any vacuum leaks, it also will tell you if there is a valve sticking !
#3
Thanks for the reply. There are no vacuum leaks and it was doing this before the engine swap so I'm thinking it's not a sticking valve. I set the timing so I believe it is correct. I'm was just wondering if it could be a wiring problem or something like that. I was hoping somebody has seen this same thing before.
#4
You didn't mention it, but have you done anything with the fuel system like check fuel pressure and/or change the fuel filter?
It would probably be a good idea to check the fuel pressure especially considering all you had done and it should perform better than it is.
It would probably be a good idea to check the fuel pressure especially considering all you had done and it should perform better than it is.
#10
Thanks for the bump. I still haven't had a chance to check the fuel pressure. I did replace the MAF and O2 sensor but that didn't help. The other day when I was driving home it started running really rich and shaking to the point that it felt more like a tire coming off than an engine shake. I turned of the OD and got the revs up and made it home. Right before I got home it actually cleared back up. the CEL came on and I had a 157 and 173 code in KOEO. So I replaced the MAF and O2 sensor. I still need to check the fule pressure but I will be out of town this week so it will have to wait till I get back.