If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
'97 GMC 350 Engine Performance
My GMC suddenly started cutting out under load. I've noticed it
occasionally missing in 3rd gear and OD so far and tried to get it to do it in 2nd yesterday afternoon but never could. Doesn't idle rough (had it tuned up about 5k miles ago at the dealer) and it's doing this around 2300 RPMs, generally on a slight uphill grade. It ran so smooth in 2nd yesterday that I'm wondering what 'emissions' type devices might be causing something like this. (noted the missing BTW as something that almost feels like a sharp wind hitting the vehicle with a momentary dip in the tack reading). Any ideas folks? |
Ads |
#2
|
|||
|
|||
'97 GMC 350 Engine Performance
On Nov 4, 1:54 pm, cover > wrote:
> My GMC suddenly started cutting out under load. I've noticed it > occasionally missing in 3rd gear and OD so far and tried to get it to > do it in 2nd yesterday afternoon but never could. Doesn't idle rough > (had it tuned up about 5k miles ago at the dealer) and it's doing this > around 2300 RPMs, generally on a slight uphill grade. > > It ran so smooth in 2nd yesterday that I'm wondering what 'emissions' > type devices might be causing something like this. (noted the missing > BTW as something that almost feels like a sharp wind hitting the > vehicle with a momentary dip in the tack reading). Any ideas folks? Wires. Fuel Filter. Don't jump to "emissions type devices" or anything else until you cover the basics. |
#3
|
|||
|
|||
'97 GMC 350 Engine Performance
dahpater wrote:
> On Nov 4, 1:54 pm, cover > wrote: >> My GMC suddenly started cutting out under load. I've noticed it >> occasionally missing in 3rd gear and OD so far and tried to get it to >> do it in 2nd yesterday afternoon but never could. Doesn't idle rough >> (had it tuned up about 5k miles ago at the dealer) and it's doing this >> around 2300 RPMs, generally on a slight uphill grade. >> >> It ran so smooth in 2nd yesterday that I'm wondering what 'emissions' >> type devices might be causing something like this. (noted the missing >> BTW as something that almost feels like a sharp wind hitting the >> vehicle with a momentary dip in the tack reading). Any ideas folks? > > Wires. > Fuel Filter. > Don't jump to "emissions type devices" or anything else until you > cover the basics. > I had a similar situation. Turned out I was losing fuel pressure inside the fuel tank. At less than full load, all was well. Max load caused a stumble. Isolation hose between pump & delivery tube leaked by hose clamp. |
#4
|
|||
|
|||
'97 GMC 350 Engine Performance
I agree on the fuel pressu
But, on the transmission slipping from second to third. If it's a 4L60E or 4L65E, there is an issue with the pressure control valve for the lock up torque converter. I would have this checked, before it costs you a total rebuild. With lots of hard parts. Now you can just have the valve body machined, or use a shift kit, with an insert type valve. RK "syoung" > wrote in message ... > dahpater wrote: >> On Nov 4, 1:54 pm, cover > wrote: >>> My GMC suddenly started cutting out under load. I've noticed it >>> occasionally missing in 3rd gear and OD so far and tried to get it to >>> do it in 2nd yesterday afternoon but never could. Doesn't idle rough >>> (had it tuned up about 5k miles ago at the dealer) and it's doing this >>> around 2300 RPMs, generally on a slight uphill grade. >>> >>> It ran so smooth in 2nd yesterday that I'm wondering what 'emissions' >>> type devices might be causing something like this. (noted the missing >>> BTW as something that almost feels like a sharp wind hitting the >>> vehicle with a momentary dip in the tack reading). Any ideas folks? >> >> Wires. >> Fuel Filter. >> Don't jump to "emissions type devices" or anything else until you >> cover the basics. >> > I had a similar situation. Turned out I was losing fuel pressure inside > the fuel tank. At less than full load, all was well. Max load caused a > stumble. Isolation hose between pump & delivery tube leaked by hose clamp. |
#5
|
|||
|
|||
'97 GMC 350 Engine Performance
cover wrote: (1997 GMC 350 Engine Performance)
My GMC is cutting out under load. It occasionally misses in 3rd gear and OD but not in 2nd. It does this at around 2300 RPM, generally on a slight uphill grade. When it misses it feels like a sharp wind hit the vehicle with a momentary dip in the tach reading). It idles smoothly (dealer tuneup 5k miles ago). Any ideas? ________________________________________ Wires. Fuel Filter. Don't jump to "emissions type devices" or anything else until you cover the basics. dahpater ________________________________________ I had a similar situation. It turned out that I was losing fuel pressure inside the fuel tank. At less than full load, all was well. Max load caused a stumble. Isolation hose between pump & delivery tube leaked by hose clamp. "syoung" _________________________________________ It's probably not the fuel delivery system because it only happens at part throttle. It's probably not the high voltage system (wires, coil, distrib, plugs), as it doesn't happen at full throttle. Some other possible causes: -- Sticking IAC -- Intermittent Igniton Module failure. -- Trans downshifting late. -- TCC engaging too soon under load. Trans and TCC errors could result from erroneous load sensors such as manifold vacuum or throttle position. Good luck. Rodan. |
#6
|
|||
|
|||
'97 GMC 350 Engine Performance
sounds like the fuel pump is not working 100%. What are your fuel
pressure test readings? |
#7
|
|||
|
|||
'97 GMC 350 Engine Performance
On Nov 4, 7:09 pm, "Rodan" > wrote:
> cover wrote: (1997 GMC 350 Engine Performance) >It's probably not the fuel delivery system because it > only happens at part throttle. > > It's probably not the high voltage system (wires, coil, > distrib, plugs), as it doesn't happen at full throttle. Yes, fuel, wires will cause this problem! > Some other possible causes: > > -- Sticking IAC > -- Intermittent Igniton Module failure. > -- Trans downshifting late. > -- TCC engaging too soon under load. > Trans and TCC errors could result from erroneous load > sensors such as manifold vacuum or throttle position. He didn't say he has transmission problems! > > Good luck. > > Rodan. |
#8
|
|||
|
|||
'97 GMC 350 Engine Performance
On Nov 4, 7:00 pm, "Refinish King" > wrote:
> I agree on the fuel pressu > > But, on the transmission slipping from second to third. If it's a 4L60E or > 4L65E, there is an issue with the pressure control valve for the lock up > torque converter. > I would have this checked, before it costs you a total rebuild. With lots of > hard parts. > > Now you can just have the valve body machined, or use a shift kit, with an > insert type valve. No where in his post does he mention "transmission" problems! There is no mention of "slipping from second to third". He is discribing a "running" problem. |
#9
|
|||
|
|||
'97 GMC 350 Engine Performance
<dahpater yahoo.com> wrote: He didn't say he has transmission problems! _____________________________________________ <dahpater yahoo.com> wrote: Nowhere in his post does he mention "transmission" problems! There is no mention of "slipping from second to third". He is describing a "running" problem. _____________________________________________ Thank you for your helpful contributions. Rodan. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Improves Engine Performance | john | Ford Mustang | 27 | October 4th 07 03:25 AM |
Improves Engine Performance | john | Honda | 0 | September 19th 07 04:59 AM |
Improves Engine Performance | john | Technology | 6 | September 11th 07 11:42 PM |
Improves Engine Performance | john | Jeep | 0 | September 10th 07 03:49 AM |
Improves Engine Performance | nico | BMW | 0 | September 7th 07 03:12 PM |